i would go with a back pack skimmer for that tank. thay are good skimmers and wil do well on a 20 gall tank and for the price the quality is very good on them. i have been seeing problems people are having with the prizam, its a newer skimmer and i think thay are still working out some problems. CPR has a really good web page for any questions you might have
I like the Bak Pak, because you can buy an overflow for it, and you can stick your heater inside of it as well. At least for the Bak Pak II. I'm not sure about the IIr
I have the 2R on a 12 gallon hex tank my heater 75 watt ebo jager in the skimmer as well as my grounding probe and bag for carbon all in the skimmer. The only thing with mine is the air side gets clogged with calcium very quickly. I am using an irrigation syringe with tank water to periodically flush the air line it seems to be working well
Sorry Jeremy, I do have a Prizm skimmer for my 46 gallon tank and I LOVE IT. It does the job real good. And it is easy to adjust. I do not understand what you mean by terrible construction. You must be the second person only that I see that does not like it. The other one had problems with all her skimmers, not only that one. Please explain what is so bad about it?
I agree with Goldmoon. I think the Prizm skimmer is the best bang-for-the-buck skimmer you can buy from smaller (less than 50gal) tanks. It is fairly quiet, performs well, easy to clean, compact and all for only $65. Just be sure to get the new replacement impeller from Red Sea, as it's quieter and more efficient than the original one.
I've had mine for over 6 months now (on a 100gal tank!) and it works flawlessly.