Doesn't a 'water softener' exchange Ca ions with Na ions and thereby just increase water conductivity as in micro-siemens? Might not this be worse for sensitive fish than just using a little bit of unsoftened tap water? I would just add regular 'on tap' to get the hardness you are after. Check www.thekrib.com to see if they have more info. I've gotten a lot of help from the material on their site. G. Kadar ------------------------------------------------------------------------- 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"!