The product is called Nitra-sorb (or -Zorb) and is made by Aquarium Pharms. It lasts about 5 days in my tank before it needs regeneration (by soaking in a heavy salt solution). I am still have it in my canister filter until the De*nitrate (by Seachem) substrate takes over. Let me know if you want to know more. I got it at Petsmart, but you can get it mail order from Pets Warehouse (and I'm sure others). Kelly Beard, Cat IV, Team Allanti President, Allanti Cycling Club - http://www.allanti.com IBM Global Services ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@majordomo.pobox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@majordomo.pobox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!