Why does my ph drop

[CBD]

A newbe would like to know why my ph drops off two days after a water change I'm using Cogo A&B in a DW system with ro water. starts off 6.3 one or two days its down to 4 or less Thanks for any info.

 

[Tater313]

Your soil runoff PH is a 4?

 

[NickyChicks]

From what I have read, RO is nearly perfect pH of 7.0... when exposed to air, which I'm assuming you're running airstones, the water drops into the acidic range. I'm also a noob so maybe a more experienced grower will chime in. I also have a DWC setup but I use tap water. My pH will increase over a 1-2 day period due to the chlorine in my tap water releasing from being aerated.

 

[SirSmksAlot]

NickyChicks is right. The dissolved oxygen will acidify your water over time.

 

[9fingerleafs]

oxygen will rise the ph (pump on 24/7) and carbon dioxide lowers ph (no air stone) but the ph can also be affected by the water to nutrient ratio, meaning the plant could be drinking more water than nutrients so nutrients are left behind and get more concentrated. whats your pump situation? do you measure ec or ppms?