Hi Ken, I don't have an ozone system but I've read about them and to keep the ozone from getting to main system you should run the ozone through a carbon chamber before the treated water gets back to the main tank. Another device to get the ozone working more effieciently is to use an ozone reaction chamber. Are you planning on using this for one tank or a system? An ozone system can get pretty pricey. Check out some of the marine aquarium online store sites for more information. Cheers, Victor Eng ----------------------------------------------------------------------- -- 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. apisto-digest@listbox.com also available. Web archives at http://lists.thekrib.com/apisto Trading at http://blox.dropship.org/mailman/listinfo/apisto_trader