RO Water filter question

[shamrock13]

I recently purchased a Coral Life RO unit. After two weeks I noticed by PH was starting to drop. So I performed another water change. After testing the water I noticed a lower PH. After hours of questioning my life I tested the RO water before adding salt an noticed it was at about 6.1. I called my lfs that I purchased it from and they told me it was quite normal for that to happen(you think he would have told me prior to buying it, I blame myself too for lack of research) I used "kent" buffer in my aquarium tank and it brought it back to normal. My question is do I have to do this every time now or is there an easier way. The guy at lfs told me to add buffer to the RO water as I'm adding salt to it. What do you guys/gals do??

 

[Firemedic1081]

That's funny that you posted that. I was just thinking about the exact same thing. I was topping off my tank and ran out of water. I was thinking that I needed to make more (buffer some of my RO water). At the same time contemplating an auto top off unit and wondering about people that have their RO unit connected to the sump. How would that affect the Ph? I would assume that it would lower it until you did a PWC. I would also assume that the swing would be bad for the inhabitants.

 

[ccCapt]

What is the pH of the water going into the RO unit? Typically a RO unit will slightly lower the pH because it removes minerals in water and the "pure" water will then react with carbon dioxide when it's exposure to air and form carbolic acids and lower the pH.

You should not need to buffer your RO water. All the major synthetic sea salt mixes will contain the proper elements to bring the water up to a pH of around 8.

I've been using an RO unit on my reef tank for over 20 yrs. I never buffered the top off water.

 

[shamrock13]

Water going into RO is 8.1ish come out 6.5-7.0
Someone recommended to put a powerhead in the bucket after I make ro water to keep a constant flow and it actually helped