Hello Bob I also live in an apartment so a blower is out of the question, so I use lots of air pumps. The whisper pumps are great and not that noisey. I have found that the Hagen Optima and Maxima pumps are the quietest ones. I have 2 different Optimas running 55 gallon tanks that I hardly hear. I don't know if I've gotten used to the sound of gurgling water or I really don't hear them so much. I hear the bubbling water more then I hear the pumps. I am not endorsing any products for those that want to jump at that thought, just giving my opinion as a hobbyest. I have used Whisper, Hagen, Penn Plax and several no name companies pumps and for quietness Hagen is the best in my mind. Now when it comes to repairing them, that's another story. After about 2 years you need to replace the diaphrams and that is a pain in the ...... Whisper pumps are the easiest to maintain and change diaphrams. Also whisper replacement parts are cheaper then Hagen. I also have a whisper 600 running a 55 gallon tank in my Bedroom and I don't hear that one either. Oh for the curious who are keeping track 3 55 gallon tanks so far. I actually have 4 55 gallon tanks, a 30 , 1 20 long and 2 ten gallon tanks in the bedroom. I said I hear lots of gurgling going on at night. It helps me sleep actually. Hope this helps Bob John ------------------------------------------------------------------------- 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"!