R/O Water Change ???

[pensky]

I made up 20gal of R/O saltwater to use for my water changes. It has a pump to keep the water moving and it has stayed around 78 degrees. It was mixed about a week ago and when I tested the water today it had 0.50 Nitrite and everything else was good. Should I use this water to do a change or should I throw it out and not make so much this time?
Also my tank water's PH has dropped to an 8.0 and the R/O water is 8.2. Should I use some buffer to the R/O water before I do the change or just add buffer to the tank directly?

 

[thegrog]

The second question is easier. Add buffer to the tank, not to your water.
For the first, that is unusual. You may have a bad test kit. Try testing just plain RO water and see if you get a reading. If you do, you got a bad test kit. I don't know why you would have nitrite in mixed water as there is nothing in there (or should be nothing) to make it. Strange. :notsure:
Aging water for a week is not necessary, one or two days is plenty if it has good circulation and aeration (a venturi powerhead is perfect for this).

 

[pensky]

I know my test are fine because I test my display tank and it was 0. the only thing I can think is that I have a tub with live rock cureing and maybe I transfer some water on my hand while I was checking the temp. Would that little of water make a difference?