Sorry for the additional post - was reading the original before discarding and should correct para 10, sentence 2: 'The "pure" water coming from the DI means that you can pinpoint a specific pH or KH for the maintenance tanks with just some simple math.' phrase should be "specific GH or KH" but then, you knew that... -Y- ------------------------------------------------------------------------- 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"!