why is my ph so unstable??

Im running a bubbleponics/dwc system, 3 plants, cfl grow. Im trying to keep my ph between 5.8 and 6.5. I get the ph to 5.8 and the very next day, same time its pushing 6.5+!! I just dont get it. I feel like im drowning my plants with phDOWN. Any help is appreciated!

What type of pH down are you using? What type of nutrients, what are the temperature changes from high to low, are you getting any algae or bubbles that do not pop as soon as they appear in the dwc?


It seems like an improper pH buffer and the hydrogen is getting squeezed out of your medium, this causes pH up - living organisms often cause this.

What is your start PH of your water?
what Nutes are you feeding?
do you clean your buckets often?

my water starts high 6.8, but the FF Nutes lower the PH to 6.3 and
then I adjust with a touch of PH down to get 6.0 in a 12 gallon reservoir.

my plant takes in water and Nutes and my PH drops to 5.6-5.7 every 2 days,
I adjust by adding my tap water to balance back to 6.0.

maybe you have a salt buildup in your buckets, Not sure if that would spike your PH.

I also want to know what you're using as pH down. Is it nitric acid based or phosphoric acid based? (or something totally wrong?)

WEST925COAST said:

Im running a bubbleponics/dwc system, 3 plants, cfl grow. Im trying to keep my ph between 5.8 and 6.5. I get the ph to 5.8 and the very next day, same time its pushing 6.5+!! I just dont get it. I feel like im drowning my plants with phDOWN. Any help is appreciated!

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I had exact same problem. I tried several "cures".
Someone said it might help to use reverse osmosis water, so I bought a system and the pH stabilized. Now it goes down VERY slowly and I rarely have to adjust.

After some research, I also found that the hydroton I am using may cause pH problems until it stabilizes. Not sure if this is true.

Maybe buy a few bottles of filtered water at the grocery store, change your res water and see if that helps.

For tap water with lots of calcium, phosphoric acid based pH down sometimes does a bad job at lowering the pH. This is because calcium phosphate is very insoluble in water. When phosphate and calcium ion levels are both high, and the pH gets too high, calcium phosphate will precipitate out of the solution, then all bets on pH are off.

Since calcium nitrate is very soluble in water, when you add nitric acid to tap water with lots of calcium carbonate, the nitrates from the nitric acid can not form precipitates with the calcium.

Products like ionic have a hard water version that replaces some of their calcium nitrate with nitric acid. You end up with the same thing because the calcium carbonate from the tap mixes with the nitric acid giving you calcium nitrate and CO2 gas.

Hey thanks for all the responses. I flush weekly with sink water that comes out with a ph of 8.5. I useGeneral hydropincs pH DOWN (Orange bottle). I dont see anywhere on the bottle what its base is. As for nutes, i use gh floraduo a and b. I have a 10 gal res and my grow medium is mother earth hydroton pebbles. On another thread i posted about yellowing leaves and possible salt buildup, someone told me i should buy superthrive and liquid karma so i did. I'll be adding it tonight. The temp in the box stays between 65-75 as it is in the garage. Thanks for everyones help!

Churchhaze: its phosphoric acid based....... Bad news huh. Do you have any recommendations on a better pH down???

What is the ppm of your tap water? It's not like having phosphoric acid is a waste. It only becomes a problem if you have very high ppm tap water. Nitric acid based will be a lot more effective and stable for very hard water though.

What you are seeing is the reaction of the microbes to the fresh water with your water changes.. They have to rebuild which will cause the fluctuation in the PH. Make sure you de-chlorinate your water. I use a aquarium de-chlorinator to clean my water of chlorine to help with this common problem. You can also leave your water out overnight and it will do the same thing. Peace

8.5 out of the faucet

churchhaze said:

What is the ppm of your tap water? It's not like having phosphoric acid is a waste. It only becomes a problem if you have very high ppm tap water. Nitric acid based will be a lot more effective and stable for very hard water though.

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8.5 out of the faucet

Jimdamick said:

What you are seeing is the reaction of the microbes to the fresh water with your water changes.. They have to rebuild which will cause the fluctuation in the PH. Make sure you de-chlorinate your water. I use a aquarium de-chlorinator to clean my water of chlorine to help with this common problem. You can also leave your water out overnight and it will do the same thing. Peace

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Thanks for the advice bud. Can I dechlorinate then just throw my plants back in our do I have to wait.

I don't like to suggest specific brands, but the only big company i know off the top of my head that uses nitric acid for their pH down is technaflora, but anything with it would work.

http://www.technaflora.com/indexProduct.php?ID=114

The other alternative with water that hard would be reverse osmosis water.

WEST925COAST said:

8.5 out of the faucet

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What's the ALKALINITY of your water? that's more important than pH...

Here's another nitric acid based product from the UK. I didn't check the price so it may be more expensive, but it has an explanation similar to what I'm giving here for hard water.

http://www.growell.co.uk/nitric-acid-ph-down.html

"
Growers in very hard water areas may need to use a lot of pH Down, but doing so can cause nutrient lock-out. Nitric Acid provides an alternative solution to reducing pH whilst also adding Nitrogen (which can be used by your plants) to your solution as a by product.

Call our Technical Team for advice on 0845 345 5176.
IMPORTANT NOTE: We cannot send/supply Nitric Acid pH Down to any UK offshore destination including Isle of Wight, Isle of Man, Scilly Isles, Scottish Islands (Western Isles, Orkney, Shetland, etc) Northern Ireland, Republic of Ireland and Channel Isles. This is due to the International Maritime Dangerous Goods (IMDG) code."

plaguedog said:

What's the ALKALINITY of your water? that's more important than pH...

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I dont know the alkalinity but im flushing tonight with alhambra filtered drinking water and seeing where that goes.

Update: cleaned my res, added my floraduo a and b and 50% dose of liquid karma then phd my tank. Last night at 9 pm my ph was 5.5. This morning and 830 am my ph is 6.8! WTF IS GOING ON!?!

"WTF IS GOING ON!" - Your pH is not buffering..


My tap water is pH @ 7.3, I have no problems at all by using a little bit of crushed Elemental Sulfur to the res. It takes a couple of days to stabilize and I use citric acid from Earth juice to get it in check until the ele sulfur kicks in. My pH stays at 6.4 and never drifts.. temp change is 15f, ppm is 3000, cior/perlite. Some people use battery acid, holy lead fuck - Batman!, some people use GH pH down, its ok, some use Earth Juice and citric acid, I use the elemental sulfur and citric acid.




The citric acid helps the krebs cycle, and the ele sulfur is one hell of a buffer.. It takes about a few days for the ele sulfur to start working in the res. after a couple of days, it turns into a white and fluffy kinda of silt, no problem with portability.

Ill check out the sulfur and citric for sure. Do you think it has anything to do with my hydroton balls? I rinsed them well but no soak, even though they never even.touch the water?