Tap water

[Xan]

I usually filter my water with an RO unit. my ppm out of tap is 35 to 40 which is pretty low. is it ok to use my tap water and let it sit out over night to dechlorinate?

 

[Beachwalker]

I usually filter my water with an RO unit. my ppm out of tap is 35 to 40 which is pretty low. is it ok to use my tap water and let it sit out over night to dechlorinate?

Yes

 

[1diesel1]

Stick a air stone in there it will speed up the process.

 

[Krisforce]

Hy, how would you make a buffer solution with KHCO3 (Potassium bicarbonate) to have a pH of around 5,5–6. It would be used in a hydroponics system to make a buffer solution in RO water (demineralized) that can resist the acidic nutrient fertilizer. Tried with 60 mg/L and 90 mg/L of KHCO3, but unfortunately, the pH drops drastically to a level of pH 4 after 4-5 days, which is not good for my plants… IMPORTANT: the system is a passive system not bubbling CO2 in the solution!!!

So, in 1 L RO water, I added 90 mg of Potassium Bicarbonate (KHCO3) as a buffer and make the solution to 90 ppm (128,6 µS/cm). This brought the pH to 7,86. Then, after half an hour I added the Nutrient Solution. 935 µL Nutri Forte A (specification attached to the comment) + 935 µL Nutri Forte B (specification attached to the comment). I stirred it. At the moment the EC showed 1203 µS/cm (1,203 mS/cm) and pH was 7,13. I added 80 µL Phosphoric acid (H3PO4) to adjust the pH. I stirred it. The EC at the moment showed 1205 µS/cm (1,205 mS/cm) and pH was 5,56 on 23,8 ºC.

The solution is in a Jar, not touching any plant only under pure air. The values changes by days:

Day0 - EC 1205 µS/cm | pH 5,56 | 23,8 ºC

Day1 - EC 1220 µS/cm | pH 5,81 | 22,0 ºC

Day2 - EC 1238 µS/cm | pH 6,01 | 21,5 ºC

Day5 - EC 1360 µS/cm | pH 4,02 | 21,9 ºC

I am asking your help figuring out how can I solve this. Should I raise the KHCO3? If yes, what should be the overall amount? What could be the problem?