by stilllearnin on Sun Aug 17, 2003 11:28 pm
If you mean a wet/dry type filter? (filter under the tank) you can either do like cichlidfish said and adjust the hose depth (if the hose,tube or whatever can't be adjusted - drill a hole in it at the level you want,once it sucks air the syphon will quit)
or if it's a system with a standpipe type drain - make the standpipe taller or if you useing an overflow box just adjust the overflow.
Or if you understand wireing you can find electronic float switches that close when power to them is cut - basically an electronic valve