> Anyone use a sponge on a 30 G - or is the tank too big? Yes. I have almost ALL my tanks using Hydro-Sponge filters. My tanks range from 10 gallon tanks (I use the HS-I) on up to 100 gallons. In the 55's I use one HS-V, and in the 100 I have one Hydro Pond (which with air driven is up to 1000 gallons and if with a power head or water pump it does up to 1500 gallons) and a HS-V. I now only have one tank left that has an UGF. It is a steel frame 55 and eventually will also be transferred over to just a HS-V. I find these work really well in my tanks. I have used the HS-I's in the 10 gallons when I had apisto's. I still use them today for breeding my corys. I especially like them in my rearing tanks. (20's to 55's) Darren has a plant tank that uses a HS-V. I really like them. Just my opinion. Kaycy ------------------------------------------------------------------------- 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"!