Kelly you ask some valid questions. I think what you need to consider is that there is no "target" tds reading. rather if your RO produces water with a tds of 4ppm and your tanks are at 300ppm you have a reading of the pollution level in your tank. the rise from 4ppm to 300ppm is the pollution level. What we strive for is to keep it as close to 4ppm as we can manage. Consider the bare bottom tank at 30ppm since there are far less places for organics to accumulate and waste is easily siphoned off. Search the archives also for more info on teh subject there is a ton. If you need more assistance thats what were here for. Good luck. Dave Sanchez --- rabidchild43 <rabidchild43@home.com> wrote: > Hello all, No one has said what the target ppm > reading on a TDS meter. I use RO and I get it at > about 4ppm, tap water is around 985ppm and the tanks > average about 300ppm. My glass bottom 10 gallon is > right at 40ppm..........Kelly > __________________________________________________ Do You Yahoo!? Great stuff seeking new owners in Yahoo! Auctions! http://auctions.yahoo.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.