Last week I did a water change and lost a neon and noticed respiratory stress on the hatchet fish. The cichlids seemed fine. I make water change water with RO unit, trash can, and appropriate KH and GH reconstituters. Irritated with the death of the last neon, I took a sample of my water to the LFS. I described to him the situation, and he was puzzled. On a whim, I asked if he could do a test for chlorine. He said "surely not", but I insisted that something was up with this water. Bingo, I was right. Ample amounts of chlorine. I found a chlorine test kit today. Apparently Nashville, TN tap is just chlorine, not chloramine. But, what I want to know is, why should an RO unit leak chlorine? My carbon unit was brand new - but there's a twist. The carbon block was purchased from Home Depot or Lowe's and is meant for a home water unit. I bought the best one, something around $33, a CB-3, made by Omni, I believe. The label said 99.9% of chlorine removed. >From what I can tell, none is being removed. I carbon block fits tight - water can't be getting around the unit. So, I ordered 4 carbon blocks meant for my Coralife RO unit from That Fish Place, thinking that maybe the carbon block is not meant for an RO unit. Maybe the flow of water is too high, or something. Well, I know quite a few people here are using RO units. Does your unit remove chlorine or what? Am I on drugs and don't know it? Anyway, it can be several days before I get the Apisto Digest. I'd appreciate it if you could CC your reply to me as well as to the group. BTW, the RO membrane is a TFC. That Fish Place catalog said "for use with chlorinated or non chlorinated water", but I think that is if you have a working carbon unit. I thought chlorine damaged TFC membranes. Thanks for any expertise! -- Kelly Beard, Cat IV (on sabbatical) President, Allanti Cycling Club Innovative Computing Corporation ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!