Quick question on maintaining a low pH: I've got a tankful (~7 in a 58G) of Dicrossus sp. "Rio Negro" that are nearly adult. I keep them in peat-filtered DI water, ammonia/nitrate 0, blah blah blah. From what I've read, these fish can tolerate (and in fact might thrive) at even lower pH's, maybe in the general vicinity of 4.0. (1) What's the best way to test pH that low? Most colorimetric tests seem to bottom out at 5.5 or 6.0. (2) What's the best way to BUFFER a pH that low? The last thing I'd want is a really unstable 4.0, since my water hardness (DI) is nearly 0. Thanks. Stuart -- Stuart Hall (sturob@swbell.net) (gasdocstu@my-deja.com) ------------------------------------------------------------------------- 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"!