ph won't stay down

calenk

Member
are there ph down products that work better than others? im currently using GH ph down but anytime I drop the ph of my drain to waste reservoir it will slowly clime back up. I'm currently using RO but I'd like to get off of it and goto just filtered tap water. its about 7.8 starting PH so it needs alot of adjustment. is there possibly a nutrient lineup that drops the ph enough that would remain stable because ph down only seems to work for a day or so.
 

Palmerrdgrower

Well-Known Member
are there ph down products that work better than others? im currently using GH ph down but anytime I drop the ph of my drain to waste reservoir it will slowly clime back up. I'm currently using RO but I'd like to get off of it and goto just filtered tap water. its about 7.8 starting PH so it needs alot of adjustment. is there possibly a nutrient lineup that drops the ph enough that would remain stable because ph down only seems to work for a day or so.
That’s all I get.
 

eyderbuddy

Well-Known Member
Lowering the PH and holding it stable are 2 different things. In a balanced system PH should remain relatively stable. Did you check for light leaks or places that could encourage bacterial growth such as stagnant spots?

GH PH down is pretty much diluted phosphoric acid, by the way...
 

Airwalker16

Well-Known Member
are there ph down products that work better than others? im currently using GH ph down but anytime I drop the ph of my drain to waste reservoir it will slowly clime back up. I'm currently using RO but I'd like to get off of it and goto just filtered tap water. its about 7.8 starting PH so it needs alot of adjustment. is there possibly a nutrient lineup that drops the ph enough that would remain stable because ph down only seems to work for a day or so.
Why would you want to downgrade from RO to Filtered Tap?
 

calenk

Member
Lowering the PH and holding it stable are 2 different things. In a balanced system PH should remain relatively stable. Did you check for light leaks or places that could encourage bacterial growth such as stagnant spots?

GH PH down is pretty much diluted phosphoric acid, by the way...
it's in a pretty light sealed res with a pump constantly circulating. when using RO water it is pretty stable. I don't use any ph down and it ends up at 6.6 which is kinda high but plants seem to be fine with it. thing is I wanna get away from Ro so it's gonna need the ph dropped.
 

calenk

Member
Why would you want to downgrade from RO to Filtered Tap?
it just a pain. takes too long to make for the amount I'm using, wastes alot of water, and is a constant hassle. yesterday it slowed to producing only about 4 gallons a day and the filters are only 3 months old. so now I have to tear it all apart and see what's the problem.
 

eyderbuddy

Well-Known Member
Tap water has buffers in place to keep the PH high in order to keep the pipes from rusting. If you need a stronger PH Down solution, make your own using Phosphoric acid or another (safer) alternative.
 

Michael Huntherz

Well-Known Member
my guess....ppm too low, acid has nothing to cling to.raise the nutes and problem goes away.
Yes. Totally.

RO is likely the problem here. If you are feeding very light nutrients (can you share what is your EC or TDS?) and RO water then you won’t have much total alkalinity which causes unstable pH, aka swing.

Use a mix of RO and tap water, is my suggestion. Your pH meter will not be accurate when testing plain RO, by the way, there is not enough EC for a non-scientific instrument (think hundreds of dollars) to measure accurately. Try 50/50 tap/RO and see how it goes.

Tapwater is not necessarily a “downgrade” from RO. I honestly cannot imagine what that is supposed to mean. Municipal tapwater varies too widely by source and even by time of year to make such an assertion viable. I use tap exclusively, but it usually comes out about 130ppm and 7.0 pH, and surprisingly safe. Look up the municipal water data for your address, OP.
 
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Michael Huntherz

Well-Known Member
I dislike AN for many reasons but their pH down is the best, sigh. As for pH up there are cheaper and better alternatives on Amazon.
Good to know, I have been thinking about diluting some sulfuric acid myself, as someone suggested, but that’s nasty stuff to have around. The scale of it doesn’t really work for me, either. I only need pH down about half of the year, when the water table is low and EC from the tap is a bit higher, and then only a little bit. AN may get some of my money.
 

calenk

Member
Yes. Totally.

RO is likely the problem here. If you are feeding very light nutrients (can you share what is your EC or TDS?) and RO water then you won’t have much total alkalinity which causes unstable pH, aka swing.

Use a mix of RO and tap water, is my suggestion. Your pH meter will not be accurate when testing plain RO, by the way, there is not enough EC for a non-scientific instrument (think hundreds of dollars) to measure accurately. Try 50/50 tap/RO and see how it goes.

Tapwater is not necessarily a “downgrade” from RO. I honestly cannot imagine what that is supposed to mean. Municipal tapwater varies too widely by source and even by time of year to make such an assertion viable. I use tap exclusively, but it usually comes out about 130ppm and 7.0 pH, and surprisingly safe. Look up the municipal water data for your address, OP.

thing is its stable with RO water but not with Tap. running about 700ppm at the moment. I'm gonna try adjusting it repeatedly to see if it eventually stabilizes
 

myke

Well-Known Member
thing is its stable with RO water but not with Tap. running about 700ppm at the moment. I'm gonna try adjusting it repeatedly to see if it eventually stabilizes
Hmmm,something like as said above is in your tap water,Epson salt also helps drop ph.
 

Michael Huntherz

Well-Known Member
thing is its stable with RO water but not with Tap. running about 700ppm at the moment. I'm gonna try adjusting it repeatedly to see if it eventually stabilizes
Something is wrong with your measurements, or I would have to guess you have biological contaminants in your tap water. Otherwise that makes approximately zero sense. Good luck in any case.
 
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