Ammonia in RO/DI water?

[strazdas]

I hope someone can help us. We did a 20% water change last night like we always do and this morning we had lost 2 fish (right now it is a FOWLR tank). So... we tested the water and found <= 0.25 ppm of ammonia so we tested the RO/DI water and found it had 0.25 ppm of ammonia.

We have never had this problem before. Does anyone have any ideas as to why we would be getting ammonia in our RO/DI water?

Thanks.

 

[ReefMon]

If your water supply is treated with chloramine you will get ammonia through a RO unit. I use the Spectapure chloramine DI unit after my RO with great sucess.

HTH
Glenn R

 

[AquaFX]

Reefmon you are on the right tract.

Chloramines is a chlorine and ammonia mix, it helps stabilize the chlorine to stop THMs from developing.

Good to stop cancer-causing agents from forming, bad for reef water.

Another good step is a granulated activated filter inline before the membrane. The carbon blocks are good, but a GAC has more surface area due to the fact none of it is taken up with binding agent. Also the GAC runs the whole length of the filter instead of from the center outward (so you get about 10 inch of contact instead of less than 1inch). The DI is the last essential step to fully remove the remaining ammonia.

Ammonia has some chemically similar characteristics as water. So it can pass through the membrane fairly easily. I believe the only other liquid (other than water) that expands when it freezes is ammonia.

Hope that helps!