Nice to meet you all from Indonesia (and an overview on my plant journey)

[Steve Johnson]

I recommended the FLEX-G, Hijau, and potassium sulfate dilutions per 50 liters of water precisely because the NPK balance and nutrient dosages are correct for your cacti and succulents. Theoretically this is the only feeding regimen you should be using if it weren't for the fact that you don't know what's in the FLEX-G and Hijau. The objection to chloride raised by Mike is a significant concern -- unless you know for sure that there's no chloride in both ferts, IMO GrowMore is a safer bet. The guaranteed analysis:

GrowMore_guaranteed_analysis.jpg (33 KiB) Viewed 143886 times

I'm sure this will be the same for the GrowMore you get in Indonesia. And you see what it's derived from -- first of all, no chloride. Now we'll break down a few things:

• Ammonium phosphate is acidic, so it'll provide some acidification of tap water. Maybe not enough to fully neutralize bicarbonates and carbonates, but partial neutralization is helpful. (We can discuss the possibility of further acidification with citric acid later.)

• The potassium sulfate in GrowMore is good, but you'll need to supplement it with additional potassium sulfate.

• Remember these calculations -- %P2O5 x 0.436 = %P, and %K2O x 0.83 = %K. GrowMore 20-20-20 is in fact 20-8.72-16.6.

8.72/20 = 0.44 on the P side of the NPK ratio (too high). 16.6/20 = 0.83 on the K side of the ratio (too low). The GrowMore needs to be supplemented with potassium sulfate and ammonium sulfate so that N, P, and K strike the right balance. If you stick with that fert plus the supplements, you won't need the FLEX-G, Hijau or any other ferts. You already gave me the half-teaspoon weight of potassium sulfate, so all I need are the weights of 1/2 level teaspoon GrowMore and 1/2 level teaspoon ammonium sulfate. From there, I'll crunch the numbers and give you the dilutions per 50 liters of water. If you insist on alternating between FLEX-G plus Hijau and GrowMore feedings, at least you'll have the dilutions for both.

By the way, 50 liters is roughly equivalent to a barrel (as in a barrel of oil). I think you said 100-150 liters per watering session -- that's a lot of water! Just out of curiosity, how many cacti and succulents do you have in your collection?

[Steve Johnson]

Hi Adi,

I just posted something new in my "Fertilizers explained" thread:

viewtopic.php?p=403967#p403967

I think you'll find it to be helpful.

[Steve Johnson]

Okay, I started my test including aquarium test strips, so I'll show you the step-by-step procedures I'm following:

• Step 1: Test the pH meter with 7.0 reference solution.

The meter read at 6.90, so I had to recalibrate it with the 4.00 and 6.86 reference solutions provided by the manufacturer. Accuracy of the new calibration was verified by reading 7.00 with the 7.0 reference solution.

• Step 2: Get a pH reading of the tap water.

Now I'll show you a little something which comes in handy for a reason that will be obvious:

Poniie_PH2022Plus10282023.JPG (133.25 KiB) Viewed 143845 times

Get a small plastic storage container and cut a round hole in the lid just wide enough to snugly fit the lower part of the meter. Pop off the lid, fill the container with water, pop the lid back on, and insert the meter's probe into the water. When I did that earlier in the evening, initial reading of the tap water was 6.99, but it sloooooowly crept up to 7.33, then came back down and stabilized at 7.30. This took 7 minutes. Adi, even though you were reading your tap water at 7.0 or 7.1, I have a feeling that its pH is higher than you thought. That's why the container will come in handy as you need to give yourself plenty of time to get an accurate and stable reading.

• Step 3: Take readings of the tap water with a test strip.

Here's what I found:

• KH = 180 ppm, alkalinity = 180 ppm, GH = 75 ppm.

Yep, my water is hard, but we need to know a little more than that -- from watertreatmentbasics.com:

• "Simple definition of hardness of water is the amount of calcium & magnesium ions present in water. It is divided in two parts carbonate or temporary hardness and non-carbonate or permanent hardness."

Let's dig a bit deeper with this from Hach (https://my.hach.com/parameters/hardness):

• "The Relationship Between Alkalinity and Water Hardness
  
  "The amount of carbonate vs. non-carbonate hardness can be found by measuring alkalinity. If the alkalinity is equal to or greater than the hardness, all of the hardness is carbonate. Any excess hardness is non-carbonate hardness."

Contrary to what I thought, plants cannot take up Ca and Mg from non-carbonates, so the good news is that I don't have any permanent hardness "gumming up the works" in the roots of my cacti. As far as carbonates go, they can be neutralized with an acidic potting medium and/or acidification of the water, making Ca and Mg available to cacti and succulents. Assuming that I can fully neutralize the carbonates, how much Ca and Mg would be taken up by the roots of my cacti? CaCO3 (the primary carbonate) contains 40% calcium, but the complicating factor here is that all carbonates are measured as though it's only calcium carbonate. Magnesium carbonate makes up about 1/3 of the carbonates in tap water, so we'll try this:

• 180 ppm KH = 120 ppm CaCO3 x 0.4 = 48 ppm Ca. MgCO3 contains 28.57% Mg. 60 ppm MgCO3 x .2857 = 17 ppm Mg.

That gives us a Ca-Mg ratio of 2.82-1. Theoretically the ratio should be 3-1 or 4-1, but in reality I don't think your cacti and succulents would be complaining about it. In fact, if the hardness in your tap water is all carbonates and your KH number is similar to mine, they're getting plenty of Ca and Mg -- adding a little bit of gypsum to your pots is bonus. The tricky part, neutralizing those carbonates, so we'll have to work on that for you.

• Step 4: Add fertilizer (and acidifier if needed) to the water, then get a pH reading.

In my case, it's the General Hydroponics FloraMicro and FloraBloom, ammonium sulfate-potassium sulfate stock solution, TPS Nutrients CalMag, topped off with 5% white vinegar as the acidifier. Final pH in the watering solution = 6.13. I poured the watering solution into a clean test jar, so I'll take readings daily and see if I get complete carbonate neutralization. And if I do, I'll know how many days it takes to get there.

[Wiandry Adi]

Now that's a lot of steps! Yes, my pH meter is quite cuckoo at the moment so I need to recalibrate it and see if I can do it right this week. I see that one can't use tap water to calibrate a pH meter and RO water (or any water that has almost zero TDS) is thus recommended. I'll work on it ASAP, which shall also cover the pH results this week.

Speaking of test strips, I've done it yesterday and found something interesting:

• Step 3: Take readings of the tap water with a test strip.

Here's what I found:

• KH = 180 ppm, alkalinity = 180 ppm, GH = 75 ppm.

Same results! Though my strip test does not list 'alkalinity' but it does list pH, and it reads... 7.8? Well, I've checked it in different lights so I can't confirm which one is right: the pH meter or the strip test (or even me; however, I do see that previously, the pH of fert solution was within range of 6 yet when I measure it yesterday, it's still on the 7 range)

The result of tap water (up); the strip fresh from its container (down)

WhatsApp Image 2023-10-30 at 08.53.01.jpeg (36.4 KiB) Viewed 143818 times

The result of tap water (left) and water from AC distillation (right)

WhatsApp Image 2023-10-30 at 08.56.30.jpeg (61.56 KiB) Viewed 143818 times

The result of the fert solution

WhatsApp Image 2023-10-30 at 08.42.15.jpeg (51.53 KiB) Viewed 143818 times

So, based on the strip test so far, I got:

Control: KH 180 ppm, GH 75 ppm, pH either 7.8 or 8
WIth ferts (Hijau + FLEX-G): KH 80 ppm, GH 25 ppm, pH either 6.8 or 7.2

If there's anything missing, I can work on them next week (maybe I can get the results of GrowMore 20-20-20's weight by this week) I just need my pH meter calibrated again.

Oh, if this helps too, I read the results under the shade of my patio, in which it may affect how the color is interpreted here. If so, I'll re-work it again next week if necessary.

Also,

Hi Adi,

I just posted something new in my "Fertilizers explained" thread:

viewtopic.php?p=403967#p403967

I think you'll find it to be helpful.

Mulder's chart! Yes, I was learning about it as you provide info about it, so what coincidence! I do see lots of things that I barely understand but I see that calcium have a 'bad' rep here since it has lots of antagonist lines. I was also learning about K:Ca ratio and... I think I fried my brain but no matter! A pain in the gluteus maximus now is better than the pain everywhere in the future. Though, this will take a while to understand...

Thanks a lot for the info, Steve! We'll see where the chart will bring us to. Also also, about my numbers of collections... that'll be answered in my garden update thread! I'll share it here when it's done. For the teaser: lots. Lots of them.

[Steve Johnson]

I see that one can't use tap water to calibrate a pH meter and RO water (or any water that has almost zero TDS) is thus recommended.

Unless your pH meter's manufacturer specifically states that you can calibrate it with RO water or distilled water, you must calibrate it with a reference solution. As I said in a previous post:

• Meters with 1-point calibration -- pH 7.0 reference solution you can buy online or at your local hydroponics shop.

• Meters with 2-point calibration -- use the reference solutions either recommended or provided by the manufacturer.

I don't know of any manufacturers that recommend calibrating their pH meters with RO/distilled water, so all I can tell you is read your meter's instruction manual carefully. If it says you can do it, excellent.

Same results! Though my strip test does not list 'alkalinity' but it does list pH, and it reads... 7.8?

I tested the pH of a test strip with tap water before I added the ferts, and I found that my pH meter's reading is more accurate. This influences whether you should or shouldn't add an acidifier to your watering solution diluted with your fertilizer(s) of choice -- and if so, how much. If you can get your pH meter to behave itself, use it and don't rely on your test strip's pH reading.

So, based on the strip test so far, I got:

Control: KH 180 ppm, GH 75 ppm, pH either 7.8 or 8
WIth ferts (Hijau + FLEX-G): KH 80 ppm, GH 25 ppm, pH either 6.8 or 7.2

You already have partial carbonate neutralization from the ferts -- good! If KH and GH go down to 0 over the next several days, pH will be the thing to keep an eye on. Of course you're still in the middle of the test, so we can't jump to any conclusions yet.

Mulder's chart! Yes, I was learning about it as you provide info about it, so what coincidence! I do see lots of things that I barely understand but I see that calcium have a 'bad' rep here since it has lots of antagonist lines. I was also learning about K:Ca ratio and... I think I fried my brain but no matter! A pain in the gluteus maximus now is better than the pain everywhere in the future. Though, this will take a while to understand...

Yeah, I barely understand it myself, but I'm trying. Let's give it a shot and see if I'm reading this right...

P and Ca are a "two-way street" -- too much P inhibits availability of Ca, too much Ca inhibits availability of P. K and Ca are a "one-way street" -- too much Ca inhibits availability of K. However, there is a critical limitation to following Mulder's Chart -- it doesn't tell us how much is too much, and this applies to all of the chart's antagonistic nutrient pathways. Now, if you think Ca has a "bad rep", remember something I pointed out from hydrobuilder.com:

• "Calcium has a similar role in plants as in humans, helping produce strong cells and root walls. This leads to stronger plants. We've recently come to understand that calcium is actually the dominant nutrient in most plants." [My emphasis]

Between the Ca in my acidified tap water and the TPS CalMag supplementing my ferts, the Ca in the watering solution is a little higher than K. No antagonism between it or P, and higher Ca is one of the reasons why I've seen substantial improvements in the growth of my cacti this year.

Thanks a lot for the info, Steve!

Always a pleasure, Adi!

[Wiandry Adi]

I see that one can't use tap water to calibrate a pH meter and RO water (or any water that has almost zero TDS) is thus recommended.

Unless your pH meter's manufacturer specifically states that you can calibrate it with RO water or distilled water, you must calibrate it with a reference solution. As I said in a previous post:

• Meters with 1-point calibration -- pH 7.0 reference solution you can buy online or at your local hydroponics shop.

• Meters with 2-point calibration -- use the reference solutions either recommended or provided by the manufacturer.

I don't know of any manufacturers that recommend calibrating their pH meters with RO/distilled water, so all I can tell you is read your meter's instruction manual carefully. If it says you can do it, excellent.

Oh, my apologies, I forgot to mention the pH buffering apparatuses (apparati?) that are included within my pH meter pack, hence your confusion:

Gambar-pH-Buffer-Kalibrasi-PH-Meter-Digital.jpg (51.63 KiB) Viewed 143793 times

They're in powder form which, according to the manual and other various sources, should be diluted with water - the almost-zero-TDS water - and they come as 4.01 (acidic) and 6.86 (neutral) while the 9.18 (alkaline) one is sold separately. The manual and the buffers' packaging state the solution shall be used at 25°C for the most accurate result. I was considering using either distilled water that can be purchased from nearby pharmacies or the water from my air conditioner which are always ready to use daily (though after measuring its TDS, I found AC water has 20 ppm, I suspect due to contaminants) and I'll be right back with the calibration results!

There are also those sold in liquid form, but so far I can't find its manual or at least any videos that show how it's done, so I'll take my chance with the powder ones.

While you're at it, I found your Cal-Mag fert's website: https://tpsnutrients.com/products/copy- ... g-complete , and I found its ingredients: calcium nitrate and magnesium nitrate (micronutrients aside; I was surprised it uses sulfate derivatives, so it's kind of a liquid gypsum, I suppose). I'd like to get some of these (not the entire fert, but its ingredients) and shall my plants get the Spooktober spirit! (though it's about to end real soon... )

Here are the candidates, in which I'll weigh them along the 20-20-20 if you greenlight them. Also, I'd like to know when these two shall be applied

Calcium nitrate + boron

Karate-Plus-Boroni-Pupuk-Kalsium-Nitrat.jpg (51.71 KiB) Viewed 143781 times

Magnesium nitrate

a2e1cc91-95e7-4a15-8380-5d15b4cec1c2.jpg (30 KiB) Viewed 143781 times

[Steve Johnson]

Oh, my apologies, I forgot to mention the pH buffering apparatuses (apparati?) that are included within my pH meter pack, hence your confusion...

They're in powder form which, according to the manual and other various sources, should be diluted with water - the almost-zero-TDS water - and they come as 4.01 (acidic) and 6.86 (neutral) while the 9.18 (alkaline) one is sold separately. The manual and the buffers' packaging state the solution shall be used at 25°C for the most accurate result. I was considering using either distilled water that can be purchased from nearby pharmacies or the water from my air conditioner which are always ready to use daily (though after measuring its TDS, I found AC water has 20 ppm, I suspect due to contaminants) and I'll be right back with the calibration results!

There are also those sold in liquid form, but so far I can't find its manual or at least any videos that show how it's done, so I'll take my chance with the powder ones.

Watch this:

https://www.youtube.com/watch?v=17n_KMsx5iY

After you do that, do this:

• Get 2 clean glass or plastic 250ml containers with lids -- if your containers are a little bigger, no problem. Completely empty the pH 6.86 powder into the first container and fill it with 250 ml distilled water (not water from your air conditioner!). Stir until the powder has completely dissolved. Do the same with the pH 4.01 powder. These are your calibration reference solutions. Keep them tucked away in one of your kitchen cabinets when you're not using the meter.

Here's the pH meter you posted on 9/22:

pH_meter09222023.jpg (63.89 KiB) Viewed 143747 times

The meter is auto-calibrated with the 4.01 and 6.86 reference solutions. But unfortunately the tutorial you just watched is for that meter, and it looks like you changed to this:

pH_meters10302023.jpg (28.49 KiB) Viewed 143747 times

If that's your new pH meter, you "traded down" to a meter with manual calibration. The meter on the right is a Milwaukee Instruments pH 600 I used for 10 years, and fiddling around in the back with a set screw and screwdriver to calibrate it was beyond being a pain in the you-know-what. Given the choice between meters with auto and manual calibration, go with the one with auto-calibration if you still have it and follow the instructions in the YouTube tutorial. Regardless of which meter you use, a container with a hole in the lid will make reading the pH of your water a lot easier, so cut the hole to the lower part of the meter's dimensions. If you need further help on calibration procedures, let me know.

All pen-style pH meters have glass sensor bulbs, so follow these basic use & care instructions:

• Do not use tap water to clean the sensor -- keep a small jar of distilled water at the ready when you clean it for use.

• Do not use anything other than soft tissue paper to clean the bulb. (I keep a box of Kleenex tissues in my kitchen just for that.)

• Always put the sensor cover on when the meter is not in use. To keep it wet, put a small amount of reference solution or KCl solution into the bottom of the cover.

Not being one to do things by half-measures, I went through a couple of extra steps with my Poniie PH2022Plus:

The_rig.jpg (128.13 KiB) Viewed 143747 times

On the left -- a plastic baggie and a rubber band over the sensor cover prevents the possibility that the reference solution in the cover will dry out over a long period of time. I use a pH meter 3 or 4 times a year at the most, and I can't tell you how many meters I ruined because I let their sensors go dry for months. I won't let that happen again. On the right -- an empty jar keeps the meter upright when it's not in use.

While you're at it, I found your Cal-Mag fert's website: https://tpsnutrients.com/products/copy- ... g-complete , and I found its ingredients: calcium nitrate and magnesium nitrate (micronutrients aside; I was surprised it uses sulfate derivatives, so it's kind of a liquid gypsum, I suppose). I'd like to get some of these (not the entire fert, but its ingredients) and shall my plants get the Spooktober spirit! (though it's about to end real soon... )

Here are the candidates, in which I'll weigh them along the 20-20-20 if you greenlight them. Also, I'd like to know when these two shall be applied...

Sorry, but you're looking at the wrong stuff. This is the TPS CalMag I use:

https://tpsnutrients.com/products/calmag-oac

Please note that it's nitrogen-free. But but but...

50-liter batches of water work in your favor because you may be able to use the N and Ca in KARATE PLUS, and the N and Mg in Magnit to replace the ammonium sulfate I had in mind for re-balancing N and P with the GrowMore 20-20-20. Just send me the weights of 1/2 level tsp. GrowMore, 1/2 level tsp. KARATE PLUS, and 1/2 level tsp. Magnit, then I'll crunch a bunch of numbers and see what we come up with.

While we're here, I'd like to revisit something I said in yesterday's post:

Let's dig a bit deeper with this from Hach (https://my.hach.com/parameters/hardness):

• "The Relationship Between Alkalinity and Water Hardness
  
  "The amount of carbonate vs. non-carbonate hardness can be found by measuring alkalinity. If the alkalinity is equal to or greater than the hardness, all of the hardness is carbonate. Any excess hardness is non-carbonate hardness."

Before I read that article, I didn't realize how important it is to know the amount of alkalinity being measured in mg/L. Remember this?

Speaking of the test kit you've recommended, I've found some candidate that may suit just right. Here's one of them: https://www.tokopedia.com/vitina/14-in- ... c%3Dsearch

Would be kinda nice if you were able to get KH, GH, and alkalinity in the same test strip, but unfortunately you can't. Since that's the case, I highly recommend that you get the 14-in-1 test strips and use them just to read alkalinity. When you do, we'll modify the quote from Hach like this -- if alkalinity is equal to or greater than carbonate hardness and general (AKA total) hardness, all of the hardness is carbonate. This may be a moot point since you and I already know that KH is substantially higher than GH in our tap water, but there is a relationship between pH and alkalinity, and I intend to find out what it is -- at least for the sake of scientific curiosity if nothing else.

[Wiandry Adi]

Oh, my apologies, I forgot to mention the pH buffering apparatuses (apparati?) that are included within my pH meter pack, hence your confusion...

They're in powder form which, according to the manual and other various sources, should be diluted with water - the almost-zero-TDS water - and they come as 4.01 (acidic) and 6.86 (neutral) while the 9.18 (alkaline) one is sold separately. The manual and the buffers' packaging state the solution shall be used at 25°C for the most accurate result. I was considering using either distilled water that can be purchased from nearby pharmacies or the water from my air conditioner which are always ready to use daily (though after measuring its TDS, I found AC water has 20 ppm, I suspect due to contaminants) and I'll be right back with the calibration results!

There are also those sold in liquid form, but so far I can't find its manual or at least any videos that show how it's done, so I'll take my chance with the powder ones.

Watch this:

https://www.youtube.com/watch?v=17n_KMsx5iY

After you do that, do this:

• Get 2 clean glass or plastic 250ml containers with lids -- if your containers are a little bigger, no problem. Completely empty the pH 6.86 powder into the first container and fill it with 250 ml distilled water (not water from your air conditioner!). Stir until the powder has completely dissolved. Do the same with the pH 4.01 powder. These are your calibration reference solutions. Keep them tucked away in one of your kitchen cabinets when you're not using the meter.

Here's the pH meter you posted on 9/22:

pH_meter09222023.jpg

The meter is auto-calibrated with the 4.01 and 6.86 reference solutions. But unfortunately the tutorial you just watched is for that meter, and it looks like you changed to this:

pH_meters10302023.jpg

If that's your new pH meter, you "traded down" to a meter with manual calibration. The meter on the right is a Milwaukee Instruments pH 600 I used for 10 years, and fiddling around in the back with a set screw and screwdriver to calibrate it was beyond being a pain in the you-know-what. Given the choice between meters with auto and manual calibration, go with the one with auto-calibration if you still have it and follow the instructions in the YouTube tutorial. Regardless of which meter you use, a container with a hole in the lid will make reading the pH of your water a lot easier, so cut the hole to the lower part of the meter's dimensions. If you need further help on calibration procedures, let me know.

All pen-style pH meters have glass sensor bulbs, so follow these basic use & care instructions:

• Do not use tap water to clean the sensor -- keep a small jar of distilled water at the ready when you clean it for use.

• Do not use anything other than soft tissue paper to clean the bulb. (I keep a box of Kleenex tissues in my kitchen just for that.)

• Always put the sensor cover on when the meter is not in use. To keep it wet, put a small amount of reference solution or KCl solution into the bottom of the cover.

Not being one to do things by half-measures, I went through a couple of extra steps with my Poniie PH2022Plus:

The_rig.jpg

On the left -- a plastic baggie and a rubber band over the sensor cover prevents the possibility that the reference solution in the cover will dry out over a long period of time. I use a pH meter 3 or 4 times a year at the most, and I can't tell you how many meters I ruined because I let their sensors go dry for months. I won't let that happen again. On the right -- an empty jar keeps the meter upright when it's not in use.

Oh my, I think there's been a misunderstanding. I'm sorry for not thinking this through (in a platform where one can mindfully review their post before posting it, ironically).

That photo with the pH buffer powders - with the pH meter accidentally included in it - is from a Google search; it's a photo for reference, to show what the buffer looks like. Wow, I really didn't think you will pay attention to that pH meter! I should've just take the photos myself. I apologize that this made you went through and through looking for a tutorial and explaining on another pH meter (in which the tutorial you posted to me, it's one of the tutorials I saw couple of times ago). I'm still using the two-points one, the same as what I've posted earlier on the thread. Clumsy me I think this may be because of my brain becoming cooked well-done after learning chemistry from crash courses

OK, so by next week, I'll give the calibration results as well as the ferts' weight. Let's hope everything will be on track. By the way, will be the alkaline strip really necessary? Since the last strip test result didn't involve alkalinity, if you insist on using alkalinity test one, I may need to redo the entire measurement all over again

[Steve Johnson]

At my age (65 going on 127), I get my brain tied up in knots way too easily these days. Okay, so the pH meter you showed me on 9/22 is the meter you're using. Did the manufacturer include an instruction manual? If so, you already know the calibration procedures. If not, then A. bad on the manufacturer , and B. I think they'll be the same as the calibration procedures for my Poniie PH2022Plus. If you need help, I'll guide you through them.

[Wiandry Adi]

At my age (65 going on 127), I get my brain tied up in knots way too easily these days. Okay, so the pH meter you showed me on 9/22 is the meter you're using. Did the manufacturer include an instruction manual? If so, you already know the calibration procedures. If not, then A. bad on the manufacturer , and B. I think they'll be the same as the calibration procedures for my Poniie PH2022Plus. If you need help, I'll guide you through them.

Thanks, I'll keep you in touch about the pH meter when I have trouble during calibrating it. However, I have yet another roaring question regarding my Cal-Mag fert:

• The Cal-Mag you're using is derived from calcium carbonate and magnesium carbonate, while mine will be from calcium nitrate and magnesium nitrate. Will there be any difference, since what you're having contains carbonate and I think I haven't using any carbonate-containing ferts for a while.

• How often shall I apply this Cal-Mag? And shall they be part of my fert routine or on its own?

[Steve Johnson]

I have yet another roaring question regarding my Cal-Mag fert:

• The Cal-Mag you're using is derived from calcium carbonate and magnesium carbonate, while mine will be from calcium nitrate and magnesium nitrate. Will there be any difference, since what you're having contains carbonate and I think I haven't using any carbonate-containing ferts for a while.

Ah, you asked a good question. I was asking a few questions about gypsum via PM with Mike, and one of his answers applies directly to the calcium carbonate and magnesium carbonate in the TPS CalMag I'm using:

They probably do something like this.....

How does calcium react with citric acid?
The calcium carbonate dissolves in the acid and when it does so it produces carbon dioxide. Citric acid can cause this reaction. It is more acidic than carbonic acid, and can react with carbonates to release carbon dioxide and water (CO2 + H2O) ....rather than use chelating agents like EDTA etc.

There is a note of citrus in the TPS CalMag's smell, so that's it -- citric acid. The reaction products (besides CO2 and H2O), highly soluble calcium citrate and magnesium citrate making Ca and Mg available to the roots of my cacti. If you need to add an acidifier to your watering solution, citric acid will do the same thing as it reacts with the carbonates in your tap water.

• How often shall I apply this Cal-Mag? And shall they be part of my fert routine or on its own?

Fertilizers and supplements are always a "package deal", hence the reason why I need to include the half-teaspoon weights of everything for your watering solution's recipe. 1/2 tsp. potassium sulfate = 3.05 grams, so I just need the level half-teaspoon weights of the GrowMore 20-20-20, KARATE PLUS, and Magnit to figure out how many half-teaspoon of each that you'll need per 50 liters of water. And of course I'll give you the nutrient ppm numbers in your watering solution.

Now would be a good time to discuss the 3 forms of nitrogen plants get from fertilizers. They are:

• Ammonium (AKA ammoniacal) N (NH4)

• Urea (CO(NH2)2)

• Nitrate N (NO3)

Ammonium N and urea make nitrogen immediately available to the plant. (Contrary to what you may have heard or read elsewhere, urea does not require bacteria in the soil for N uptake.) On the other hand, nitrate N must be converted to ammonium N in the plant's tissues, and the conversion process takes place with Molybdenum (Mo). You'll notice that it's one of the micronutrients in GrowMore. A little bit goes a long way, and with ferts that are mostly nitrate N, Mike recommends .05 ppm (that's 50 parts per billion) Mo in the watering solution. The GrowMore is mostly ammonium N and urea, so when we add nitrate N from KARATE PLUS and Magnit to your watering solution, the question is -- will the Mo in GrowMore be sufficient, or should you supplement it a little bit? We'll get the answer after I crunch the numbers and give you the right recipe.

The nitrogen in my watering solution is about 1/3 ammonium N and 2/3 nitrate N. Unfortunately the Mo in my General Hydroponics FloraMicro isn't nearly enough, so I supplement it with just a bit of sodium molybdate. Yeah, I know -- sodium, but when we're dealing with something like .05 ppm, that's not anywhere near to being a problem for plants. If (and I mean if) you need to do the same, worry not at all.

[Wiandry Adi]

Alright, so the Magnit fert has finally arrived. The results - along with the calibration result - shall be arrived by this weekend. It turns out magnesium nitrate fert has been rarely distributed if not manufactured nowadays, and the magnesium carbonate one turns out to be the powder used for climbing and related sports, so it is available in gyms.

Also, about carbonate... I think as long as carbon dioxide is still abundant in the air (in which Jakarta is well known for), I think I should be fine

[Steve Johnson]

Hi Adi,

If your pH meter didn't come with an instruction manual, I think its calibration procedures with be the same as the procedures for my Poniie2022Plus. I'll walk you through them:

• Keep your containers of 6.86 and 4.01 reference solution at the ready.

• Turn the meter on and push the CAL button. The screen will flash SA 1. Dip the sensor bulb into the 6.86 solution and keep it there. The screen will flash a 3-digit number.

• When it flashes SA 2 move the meter over to the 4.01 reference solution and keep the sensor bulb in the solution while the screen flashes a 3-digit number. When it flashes End, calibration is complete.

Turn off the meter, clean the sensor bulb with distilled water, turn it back on, and get a reading of the 6.86 reference solution. If it reads 6.86, the calibration is accurate. I originally recommended that you buy a bottle of 7.0 reference solution to see if the meter needs to be recalibrated, but you can do that with the 6.86 and 4.01 reference solutions.

By the way -- I ran my Day 3 test last night, and I had to recalibrate the meter again. Always check yours in case it needs to be recalibrated whenever you use it. While I'm thinking of it, I have a hint for you...

Read the test strips and color chart horizontally, not vertically. If you read vertically, water dripping down the test strip changes the colors -- not good for accurate readings. I found that out the hard way when I messed up on my Day 3 test.

[Wiandry Adi]

Finally, the results are here! The pH meter calibration process turned to be more complicated than I thought, but I’ve done it. Just like what you’ve told, Steve, I’ve used distilled water (in which I measure its TDS and it has 4 – 0004 siemens – on the result, at 26°C) and the results were as expected. To bring more accuracy, I also used the pH 9.18 solution so there should be a balanced reading for acidic, neutral, and alkaline results.

The tap water pH reads 7.40, even after each calibration. Judging by the results from the previous test, I think there’s an influx of pH which may be unnoticed by the masses.

Screenshot 2023-11-06 082902.jpg (74.65 KiB) Viewed 143591 times

Screenshot 2023-11-06 082922.jpg (71.1 KiB) Viewed 143591 times

The water hardness results are also here! From the strip test, based on the fert solution that has been sitting for 7 days plus, the results are:

• GH : 25

• KH : 40

• pH : 6.8

So, based on the strip test so far, I got:

Control: KH 180 ppm, GH 75 ppm, pH either 7.8 or 8
WIth ferts (Hijau + FLEX-G): KH 80 ppm, GH 25 ppm, pH either 6.8 or 7.2

I see there's a progress in KH but not really close to 0 ppm, though the GH one is still the same.

And here are the results of ferts’ weight (as always, the mean/average of ten weighing attempts)

• KARATE PLUS : 4.31 gr

• Magnit : 3.12 gr

• GrowMore 20 : 2,67 gr

Now let the counting begin! *cue air horn noises

[Wiandry Adi]

Quick update: it's raining yesterday! It was pouring hard last night and I saw no news regarding any cloud seeding attempts, so it's natural rain once again! I've yet to re-measure my tap water's pH as the rainfall might affect the numbers and hopefully, it returns to the good ol' 7.0. Also, I need to be more vigilant for the temperature and humidity + how much rainfall will be in the near future.