PH rising 1.0 to 2.0 OVERNIGHT!

Ok I have been growing for a few years now and still feel like a noob. Bout a month ago I finished my new aeroponic setup. Its just a plywood box 2' tall, 2' wide, 4' long box lined with 6 mil black plastic. I have 16 clones in it. 8 Critical Kush, 4 Big Bud x White Widow, 2 Purple Haze and 2 Pineapple Express. I have a 620gph pump running a manifold with 23 mister nozzles and a 10 gal res, its the biggest I can go with for space reasons. I run PH adjusted tap water with sensi bloom a/b. Nothing else. My problem is no matter what I set my PH to, by the next day it's up to 7.0 and will climb to 8.0 by the day after. I have tried using the standard phosphoric acid to adjust with and lemon juice and aquarium sulfuric acid and it climbs just the same no matter what I do. There are no light leaks and the res sits on the cold concrete floor so it stays between 62° to never going above 70°. I always set PH to 5.5

nice for one. what are your PPMs at? u said sits on a concrete floor 62-70 im assuming thats water.

I have my ppm's set at 1000. They have been staying pretty consistent. I have had PH probs with this tap water. I ran dwc for 2 years and it's always wanted to climb but it was 1.0 in 5 days to a week. I never seen it happen like this over night. Yes that's my water temp inside the res. I think it's either the nutes or the water I just don't understand why. Its like the pump speeds up the rising.

I hear you, well if temps are in check the only thing i could think of would be make sure ppm tool is working(meter calibrated) or flush the res and drop the PPM to maybe 500? depending on what your tap water is at (looks like you're around flowering) with some fresh water/ lower nutes. Also i wouldnt think its the tap water depending on your districts water report i know mine is like 280PPM and has some strong buffering ability. I'd imagine it being alot harder to rise in ph as opposed to distilled water from the store. I'm a noob but I read a few big books on growing and experienced this myself from just water temps. My only suggestion would be just make sure your tools are working first then look into the nutes keep the same water see how that goes and then if that isnt the case checkout the water to diagnose the problem. Anyone else here that has more experience than me might know something more

I lowered my ppm to 600 using fresh tap water ph'd to 5.5 with lemon juice (it's all I have till I order more phosphoric acid). That was at bout 3 and just checked 5 min ago and it's up to 7.5 again. That's 5 hrs. It must be the water. My water only has a ppm of about 120 but absolutely WREAKS of chlorine. I'm just gonna have to go buy distilled water. So distilled is better than spring or purified water?

Puzzling!
I'm going to follow this thread.
I'm curious to hear what's happening and how it can be remedied...?

Lemon juice is crap. Phosphoric acid is good, but nitric acid is better.

Having a higher ppm nutrient solution also generally provides stronger buffering than a low ppm solution, thus is more resistant to pH changes.

0vergrown420 said:

I lowered my ppm to 600 using fresh tap water ph'd to 5.5 with lemon juice (it's all I have till I order more phosphoric acid). That was at bout 3 and just checked 5 min ago and it's up to 7.5 again. That's 5 hrs. It must be the water. My water only has a ppm of about 120 but absolutely WREAKS of chlorine. I'm just gonna have to go buy distilled water. So distilled is better than spring or purified water?

Click to expand...

0vergrown420 said:

I lowered my ppm to 600 using fresh tap water ph'd to 5.5 with lemon juice (it's all I have till I order more phosphoric acid). That was at bout 3 and just checked 5 min ago and it's up to 7.5 again. That's 5 hrs. It must be the water. My water only has a ppm of about 120 but absolutely WREAKS of chlorine. I'm just gonna have to go buy distilled water. So distilled is better than spring or purified water?

Click to expand...

Distilled has pretty much nothing in it with very little buffering ability plus you'll need to add CaMag to it. Upto you

I'd go with mountain spring make sure it says that not just drinking water. You want your good minerals.
Heres a water report for nestle...shows differences between RO, Spring, Distilled
http://www.nestle-watersna.com/asset-library/documents/pl_eng.pdf

My tap water is EC0.5
so I collect rain water
and mix 60% rain with 40% tap
This gives me EC0.2

But the pH can vary from 6.0 to 7.2

I tend to add my base nutes, Rhiz and Zym
get to 0.1 below my ideal EC
then start adjusting the pH.

I use Essentials pH Down
in a 5% solution.

If you are adjusting the ph of water prior to addingnutrients you are compromising the pH buffering capacity of the nutrients.
Typically a slowly rising pH is beneficial because itincreases the availability of different nutrients.
A rapid rise in pH can be because the nutrient strength is toolow, it can also be cause by a bacteria.
Chlorine is not your problem.
You might try a differentnutrient like dyna-gro at 5ml a gallon in tap water, it is very ph stable

Thank you to everyone for your suggestions and input! I went with the cheap option and got 10 gal of spring water an set the PH and added nutrients. Ppm 575
PH 5.3
Temp 67
I will check at 7 when lights come on and see what the damage is.

I ended up getting apple cider vinegar and it still goes up to 7 in 12 hrs. I doubt it's the nutes I can't find anywhere that someone has the same prob with sensi bloom. Its got spring water and I set the ppm to 1190 and it's working a lil better. I was reading a thread about a guy " stinkbud" and he runs NFT at 2000 to sometimes 3000 ppm. Should I up my ppm some more?

I figured it out! I'm back to using sulfuric acid and it's held 5.5 for 12 hrs now. I had to adjust 3 times in 45 min but after the 3rd time it was good. I am switching my nutes though. I just ordered the whole line of Humboldt Nutrients Organic. Now I understand that it's not 100% pure organic but for an aero system it's about as organic as I'm gonna go. I will be brewing and feeding with a tea mixed with the nutes. I just got all the proper timers and a powerful air pump so I can brew the right way. Has anyone ever used Humboldt Nutrients? I'll take pics of the babies when lights go on at 7