PH Dropping quickly?

[latewood]

I have a much harder time keeping pH consistent with RO water then with water out of the tap. With 18-20 gallon bubblers, I have to adjust pH down every day. The larger the reservoir, the less it needs to be pHed. This is one of the reasons I went with a large recirculating dwc settup. Complicated to setup, theoretically easy to maintain.

PS. Having grown 2 to 4 plants per 20 gallon containers I will never put more then 2 per 20 gallon container and I will train them away from eachother. DWC has explosive growth. I was given a 4 plant 20 gallon bubbler and it was a dissaster, even after flowering immediatly from clone.

then you have other issues...the easiest way to have a consistant ph level is using ro water. Now I don't know what nutes you are using, but It is a lot harder to have consistant ph with tap watrer due to impurities and metals squewing the ratio's, and causing reaction's that in turn change the ph

I have absolutely no ph problems at all in drip, or dwc or any method using ro water. Now I use 3-part...and always will, So I cannot say about other nute formulas:smokin:

[MisterE]

Well, last evening my PH was reading 5.8 and this morning it was 5.1. Seriously, can someone explain to me ANY reasons why the PH in water drops? Whether it pertains to hydroponics or not, I'd love to hear it.

I spent some time peeking ever so carefully into my grow tub to see if I could spot any light leaks for example (even though from what I've read if I had algae, it'd create rising ph). I patched up a couple of pinhole light leaks. Nothing much else to report though.

I've tried searching the board as I mentioned, but the search function wont work on "ph" because search terms need to be at least 3 characters, lol.

[xcrispi]

hey mr. E ,
did you wash the hell outa your hydroton before you used it ?
crispi

[MisterE]

Yes, even though it was brand new hydroton, I rinsed and scrubbed and rinsed again before I used it. It hasnt done this forever, it started some time after I got my water filter strangly enough. The water goes in at 6.0 on the dot, 10 PPM or so, and if left alone it'll drop to 5 (a 10 fold difference!) within a few days if I dont use PH Up.

Would salt buildups cause drop in PH? Would anything sickness in the plant cause it? Bacterias? Molds? Fungi? Anything? I feel like I'm not seeing the forest for the trees so to speak, and it could be simple.

I'm ordering up a gallon of florakleen in the next day or so I think, but I sure wish I knew of any specific causes. With my luck I'll run it in there and it'll recur anyway.

Remember, my plants have also been showing what LOOKS like calcium or magnesium deficiencies for a long time, and thats never gone away. Now I've read that root rot can appear in the leaves similar to a nutrient difficiency, but would it cause the PH to drop? That seems backwards. They also dont look bad or smell bad.

Well I still have some hair I havent pulled out yet, so thats a blessing Plus both plants have definitive female pre-flowers on them which is good too.

[Flower Child]

Ec goes up, PH goes down=plants require less nutes.
Ec goes down, PH goes up=Plants require more nutes
Ec stable, PH goes up=Equilibrium=Good thang.
FC

[MisterE]

Thanks, Flower Child.

If it's that simple, I'm surprised I havent seen it before, but I dont know of many resource sites to look up information frankly.

So theoretically, after some number of days on plain RO water like I have been for a few days now, I should see PH stabalize, then turn towards rising. I'll keep an eye on it. At the first hint of rising, I'll consider a weaker diet for them.

[Weedhound]

I never knew that!

[MisterE]

Well, been 5 days now on nothing but RO water and the PH is still dropping a few tenths per day. Initially I added about 30ml of H2O2 to the res (10 gallon full capacity), and only PH Up since then. PPM is 30. I've needed to add 5ml of PH Up per day, approximately. Been topping up with plain RO water as needed.

Plants are growing, but I'm still kind of amazed that the only reason I've seen posted for PH to drop is too much nutes and nothing else. I can't even find another post anywhere here with a "ph dropping" issue.

Maybe I should just run half RO and half tap water, to make use of the PH buffers in the tap water? Or maybe 1 gallon out of 10? Any input on that idea appreciated as well.

[Weedhound]

Do you have a way to check EC? I do on my meter but I never really use it...always go with the ppms....I have actually had 2 of my 8 today come up with a lower ph but Im wondering if perhaps I used too much ph down yesterday.....obviously that wouldn't be your problem...just babbling....if I see it again I will check EC on my plants. I'm not sure that there ARE buffers in tap water.....just shades of either acid or alkaline with no stabilizers. Or perhaps more than shades......

[MisterE]

Hi Weedhound. No I only have a TDS meter, but isn't it just math to determine Ec?

I believe most tap water has ph buffers. Also, before I had my RO filter and used only tap water, the ph was always high and it took quite a bit more ph down to bring it down. With RO water, it'd only take 2 drops where it used to take 10mls. Thats the buffering capacity in action.

I did some reading on icmag forums, and there is a nice thread about water including PH and buffering capacities and such and such. If I add sodium bicarbonate (NaHCO3), (baking soda! lol) it should increase the buffering capacity without increasing the waters hardness. But I'm leary of trying it, and leaning more towards simply including some of my higher ph tap water first.

I peeked at my roots today and noticed some roots heading into my drain pipe. I gently fished out about a foot long group of roots, lol. I had visions of waking up one fine morning and my entire room is flooded, circuits blown etc etc. Gonna have to rig a barrier that blocks roots, but allows water to flow freely... yikes.