New hydroponic setup - pH remains 7.0

[steve47]

Hi everone, its been a while since my last post but i finally upgraded to 1x1x2 Homebox, dripping system, etc..
I have reversed osmosis that fills a 120L tank. From that tank i take 60L into the other tank for mixing with nutes.

I have mixing pump and watering pump. I let the nutes mix with the water for few good hours and then test my PH (after tunning the PH meter in the hydro shop).

I add "PH minus" (maybe 1/4 a bottle already) to get to 5.5...
The next day it was back to 7.2.. I added like 10-15 drops and it lowered to 7.0.............
But when i "PH Plus", i need like 1 drop maybe to get it to 8.0+..

I'm not running the water in circulation so i don't re-use the water.
Also, i didn't refill the mixture tank.
After watering, the mixture goes down the toilet.

What am i doing wrong please?? Time is ticking!

 

[iwltfum]

Sometimes pH adjusting can be unpredictable. It has alot to do with your ppm's.

If you add 2ml of pH down to a solution and it drops 1 point, then adding another 2ml of pH down will not necessarily drop the pH another point. And conversely, adding 2ml of pH UP to that same solution will not necessarily raise the pH up by 1 point either.

It sounds to me like you have a bacterial problem in your res. Bacteria likes a high pH and, if it's allowed to take hold, will try and lock the fungus out by stabilizing the pH somewhere above 7.5 or so. If that's the case, then when you add pH down, it has to fight against all the bacteria and the stabilizers they put out to adjust it a decent amount, causing you to have to use much more than you would expect. Conversely, the pH up is just adding strength to the alkalinity of the water by working with the bacteria and stabilizers so it takes very little to adjust the pH alot. Cheers. Hope this helps.

 

[steve47]

Thanks!
I tried to lower the water level to about 20L/60L and then to add more "PH Minus" and it seem to work.
About the Bacteria you mentioned.. Will stabilizing the PH can solve the Bacteria problem?

Should i pour it all and make new water/nutes?
Can it be because of humidity inside the reservoir (water/nutes)?
Should i make holes for air to come in?

 

[iwltfum]

Thanks!
I tried to lower the water level to about 20L/60L and then to add more "PH Minus" and it seem to work.
About the Bacteria you mentioned.. Will stabilizing the PH can solve the Bacteria problem?

Should i pour it all and make new water/nutes?
Can it be because of humidity inside the reservoir (water/nutes)?
Should i make holes for air to come in?

I would think about it more like: solving the problem will stabilize the pH
A microbial or enzyme product meant for keeping growth at bay would probably be your best bet. Hydroguard or z7 seem to be the most popular, but their are a couple other ones out there.

Are you aerating the 60L res with an air pump and air stone?
Can you explain what you mean by making holes in your res for air to come in?

 

[steve47]

For now i have no holes and i use no water pumps, neither air stones..
But i don't want to be dependent on more products.. I want to understand why this is happening to me and how can i make it better.

I do have a pump used for mixing the water but the water tank is sealed

 

[OldMedUser]

Do you have a ppm pen to check your RO water? Sounds to me like your membrane may be shot and you're getting tap water out of the unit. Hard water would explain the problems you describe. TDS pens are cheap and worth having to at least know for sure what you're working with. Good RO water has no real pH of it's own and can swing wildly with just a drop or two of up or down. Carbonates in the water will allow you to drop the pH temporarily but then it goes back up as the carbonates use up the acid in the pH down.

A cheap air pump and stone would be a good investment too. I aerate all the water I buy for my plants.

L8r

 

[iwltfum]

A cheap air pump and stone would be a good investment too. I aerate all the water I buy for my plants.

Agreed
Steve47, you shouldn't leave your nutrient mixture un-aerated for more than a couple hours. Most feed charts recommend either aerating nutrient solutions or using them within a couple of hours after mixing. Leaving it to sit stagnant can create populations of anaerobic microbes, which aren't very great for your plants.

 

[steve47]

Thanks everyone for your help!