RO Chemistry

[cookinwood]

So besides being new to reef2reef, I also brew beer. I utilise an RO/ALK+ system on my tank. I am also asking this question on a local brewing forum as well. Recently I mixed my water for beer with this system where I usually use 3g of citric acid to non ro water to get a 5.2ph after 5 micron filtration on 7.4ph, after 3g of citric on ro it dropped it to 3.6ph on the ro/alk+. I dumped that water and went back to my regular whole house filter 5 micron... But tonight, I used to in my mash tank with .4g citric acid and got 5.36ph which is perfect.... My question to the group is for tds. Why does acid effect RO water so drastically??? This is not just a beer question, but also a reef question on why acids drastically effect water profile?

 

[Randy Holmes-Farley]

Why does acid effect RO water so drastically??? This is not just a beer question, but also a reef question on why acids drastically effect water profile?

It has no other pH buffering to offset the acid addition. Things like bicarbonate in the water will slow the drop to lower ph as acid is added because they take up some of the acid.