Hi I think Robert was the one who asked about undergravel filter for the first time, I had some difficulties finding the first message on this topic. So Robert if you want the UGF in a planted thank I would say don't do that if you want an UGF in a non planted tank I would say yes but it depends on you. If you want to raise fry than maybe a sponge filter will be the best, if you want a very good filter but problems with fry because of the suction valve you can try with biofilter or wet/dry. I had problems with this filter but solve it with a very fine sponge in front of the valve (however the wastes will remain in the aquarium and will be not sucked up by the filter). I wouldn't use also a RFUGF not good for plants and not good for fry. Anyway if you want some more motivation about these opinions I will e-mail you, I don't have much time now. Bye Simone Vicini (psvicini@mdnet.it)