Can't get my watering pH straight after adding CalMag.

luiz9733 · Nov 22, 2021

Hi guys, as a new grower my struggle is with my watering pH after dissolving 1g of Calmag in a liter of tap water. My tap gives me a 7.2 pH and 30 ppm, after adding Calmag if bumps to 8.5pH and 124 ppm. Then I start adding drops of pH down solution (chloridric acid) until the pH reaches 6.5... everything looks fine for a few minutes until the pH begins to go up for no apparent reason. Usually it goes all the way up to 8 again, then I add more pH down bringing to 6.5 and it goes up again, etc... can't stabilize at 6.5! By adding that much acid I end up with a very high ppm (I guess the pH down solution adds particles to the water) and still not able to stabilize the watering pH on 6.5, what am I doing wrong here?

Thank you.

growsince79 · Nov 22, 2021

luiz9733 said:
Hi guys, as a new grower my struggle is with my watering pH after dissolving 1g of Calmag in a liter of tap water. My tap gives me a 7.2 pH and 30 ppm, after adding Calmag if bumps to 8.5pH and 124 ppm. Then I start adding drops of pH down solution (chloridric acid) until the pH reaches 6.5... everything looks fine for a few minutes until the pH begins to go up for no apparent reason. Usually it goes all the way up to 8 again, then I add more pH down bringing to 6.5 and it goes up again, etc... can't stabilize at 6.5! By adding that much acid I end up with a very high ppm (I guess the pH down solution adds particles to the water) and still not able to stabilize the watering pH on 6.5, what am I doing wrong here?

Thank you.

What are you watering that you need to ph 125ppm? Probably doesn't matter in soil and if its hydro the nutes will bring the ph down.

growsince79 · Nov 22, 2021

luiz9733 said:
Hi guys, as a new grower my struggle is with my watering pH after dissolving 1g of Calmag in a liter of tap water. My tap gives me a 7.2 pH and 30 ppm, after adding Calmag if bumps to 8.5pH and 124 ppm. Then I start adding drops of pH down solution (chloridric acid) until the pH reaches 6.5... everything looks fine for a few minutes until the pH begins to go up for no apparent reason. Usually it goes all the way up to 8 again, then I add more pH down bringing to 6.5 and it goes up again, etc... can't stabilize at 6.5! By adding that much acid I end up with a very high ppm (I guess the pH down solution adds particles to the water) and still not able to stabilize the watering pH on 6.5, what am I doing wrong here?

Thank you.

Something don't sound right. 125ppm should only need a few drops to bring it down. All the calmag I've used has been pretty neutral ph. What are you using to check ph? What type calmag and how does the ph of your calmag compare to the other kind?

KrazyDave · Nov 23, 2021

You're adding calmag first and letting it sit for a bit right?

luiz9733 · Nov 23, 2021

growsince79 said:
Something don't sound right. 125ppm should only need a few drops to bring it down. All the calmag I've used has been pretty neutral ph. What are you using to check ph? What type calmag and how does the ph of your calmag compare to the other kind?

It does come down easily, just won’t stay there for long. I used a calibrated ph pen and drops, both confirms that the ph goes back above 7.0 after a while. I can’t see how calmag can be neutral, it is always alkaline.

KrazyDave said:
You're adding calmag first and letting it sit for a bit right?

Yes, mix well with water… let it rest for hours, remove the deposit powder from the bottom, pass thru a coffee filter then ph it down but after a while ph goes up again. Today I added drops until ph went all the way to 3.5 and a few hours later is already at 6.0 and rising.

Aqua Man · Nov 23, 2021

What brand of PH down and cal mag are you using?

Something is not adding up and I'm gonna guess it's like the lack of alkalinity and source of acid used.

KrazyDave · Nov 23, 2021

Is this before you give it to plants?

luiz9733 · Nov 23, 2021

I use FatCrystal Calmag and the pH down solution is a simple combination of distilled water plus Chloric acid. Prepared before watering the plants but can’t stabilize the ph by any means no mater how many drops of ph Dow I put in it. It always goes up after a few hours of rest.

KrazyDave · Nov 23, 2021

Have you tried just pHing plain water? Maybe your pH meter is faulty? I'm just guessing now though, this has me stumped.

luiz9733 · Nov 23, 2021

KrazyDave said:
Have you tried just pHing plain water? Maybe your pH meter is faulty? I'm just guessing now though, this has me stumped.

I have not, will give it a try on plain water... but the meter is calibrated and I confirmed the situation with one of those pH drops... they all show the same.

growsince79 · Nov 23, 2021

luiz9733 said:
I have not, will give it a try on plain water... but the meter is calibrated and I confirmed the situation with one of those pH drops... they all show the same.

Just tested GH calmag 7.6 @ 165ppm so slightly alkiline. Let sit 15min and add a few drops of FF ph down and it went to 6.5. 2 hrs later 6.6.

luiz9733 · Nov 23, 2021

So I’m doing something very wrong here, maybe the fish tank ph down solution has something to do with it. I’ll give it a try on some lemon juice.

growsince79 · Nov 23, 2021

luiz9733 said:
So I’m doing something very wrong here, maybe the fish tank ph down solution has something to do with it. I’ll give it a try on some lemon juice.

You could just add a few drops of nutes.

Aqua Man · Nov 23, 2021

Ok get im just gonna blunt and ot bother looking those up.

Buy a bottle of calmag and get phosphoric acid PH down.

If using RO you must add an alkalinity buffer. I promise you your cal mad doesn't not and that's your issue.... you have NO alkalinity and that makes for a very very very unstable PH and high fluctuations.

You first clue is it tKes very little acid to lower the PH.

Edinburgh · Nov 23, 2021

Add a bit of white vinegar to a 16oz cup of water stir and give plant go easy you can always repeat, baking soda will raise it same drill just go easy! I find this works much better than pH up/down.

Aqua Man · Nov 23, 2021

Edinburgh said:
Add a bit of white vinegar to a 16oz cup of water stir and give plant go easy you can always repeat, baking soda will raise it same drill just go easy! I find this works much better than pH up/down.

Please don't do this and no it absolutely doesn't. In soil you can but it absolutely isn't even needed to PH adjust your nutes for soil anyhow.

tobh · Nov 23, 2021

Aqua Man said:
Please don't do this and no it absolutely doesn't. In soil you can but it absolutely isn't even needed to PH adjust your nutes for soil anyhow.

+1. Keep cooking supplies in the kitchen. Same with lemon juice. Get some proper buffers if you're going to be serious about growing. They're cheap and do exactly what one expects them to.

luiz9733 · Nov 23, 2021

Just bought some hydroponics pH down phosphoric acid based solution and should arrive tomorrow, this should fix the issue according to the manufacturer of Calmag, apparently the fish tank stuff is not suitable for this. I’ll let you all know how this turned out. Thank you!

Saul.Goodman · Nov 23, 2021

Just a note, my GH CalMag raises my PH by 1.0 when using 5ml/gal which is the "general recommendation".

Aqua Man · Nov 23, 2021

OP please read carefully and if you have questions after let er rip.

Just saves me time in reposting info many times.

Marijuana pH Levels for Growing Weed: A Basic Explanation

In this article, we discuss proper pH levels for your weed plants; alkalinity, soil pH, tap water, and the effects of nutrients on pH when growing marijuana

www.thcfarmer.com

Can't get my watering pH straight after adding CalMag.

Can't get my watering pH straight after adding CalMag.

luiz9733

growsince79

growsince79

KrazyDave

luiz9733

Aqua Man

KrazyDave

luiz9733

KrazyDave

luiz9733

growsince79

luiz9733

growsince79

Aqua Man

Edinburgh

Aqua Man

tobh

luiz9733

Saul.Goodman

I just wet my plants...

Aqua Man

Marijuana pH Levels for Growing Weed: A Basic Explanation

Privacy & Transparency

Privacy & Transparency