What I meant was that I add RO-, peat filtered water or a combination to achieve the desired effect. As Mike says, all peats are not the same. Ask for a sample so you can test. A really good peat should or can drive the pH down to about 3.8 if you filter heavily with it. As for TDS, my tap has about 170- 190 microSiemens/m and after peat-filtration it is down to 100-120. /Fredrik -- Fredrik.Ljungberg@saab.se Flutter and Loads Department, Saab Ab voice +46 13 18 54 60, fax +46 13 18 33 63 ------------------------------------------------------------------------- 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.