My plant is somehow raising my pH uncontrollably...

When I mix my nute solution, I set the pH to 5.8. After 24 hours in the res (DWC Setup), the solution goes up to 7.0, and no matter how hard I try, I cannot get the pH to stabilize at anything lower than 6.7. No matter how much pH Down I add to the res, it will always go back up to 6.7.

This only happens when the solution is in the res. When I mix my solution in a spare tub 24 hrs [in advance, I can set the pH at 5.8, and it will stay at 5.8 until I add it into the res. Then it jumps up to 7.0 within a few hours.

How is my plant causing this pH change? I washed all my hydroton in advance. How can I get the pH to stabilize at 6.0?

just keep at it ... it isn't your plant raising the pH, it's the Hydroton ... ya need to pre-soak and flush Hydroton thoroughly, for a few days prior to using it ... it should settle down after awhile ... good luck :smokin:

?? Are the containers the same ? mix and DWC ? In DwC you don't have a pump running mix over hydrotron so it shouldn't wash it down much. Just an air stone in tank ? Very curious. Are the mixing and DWC in the same room ? Heat or cold maybe a factor. Kind of sounds like DWC maybe heating up under lights and giving you problems

I mixed city water with R/O water and had a hell of a time almost a week of ph downing everday to stablize.

What about your roots any sign of rot ? Can cause a problem like that.

Tell us more but like said keep at it.

The plant is on its third week, so wouldn't the hydroton be clean by now? i washed it all before I used it and I've been using it for 2+ weeks. I have one tub for mixing the nute solution, then I pour it into another tub which is the actual reservoir.

Right now in the rez are two airstones. the temp of res is about72f. the temp around the plants is about 78. Could it be the airstones?

My roots look OK i think. All of them are nice and white. reesrvoir is light-tight so i dont think its algae.

Everything sound cool. Only one more question.

What is your water source ?

I tried to mix in half city water and it, I assume the chlorine gave me a fit for a week untill it stablized..

It's not the airstones or everyone would be on here asking.

You don't have any drip ? That would wash down hydrotron so I don't see that as a problem.

Like reaper said keep at it. Something has changed with your water I bet.

what nutes are u using? I have it down to a science with Latewoods GH schedule and by using RO water and the recommended 8ml/gal pretty muck brings it to 5.8, it raises a hair the next day and then 1.5 ml of down per 2gal levels it out till the next change/1wk. Water temp may become problematic. optimal, 65-68 deg. If you are using hard water, it is hard to stabilize. Be careful of using too much down, it can flocculate with calcium and make some shitty gypsum in ur tank.