[Symbiosis]

If I were going to remove an undergravel filter, I would transfer all my live rock and livestock to a rubbermaid that would hold it all with water from the tank. Smaller containers would work to, but keep all the live stock you can in one, that way the container with the livestock has a powerhead to keep it oxygenated and a heater. Then just take out the UG, and wait for the cloud that will result from disturbing the substrate to settle. If you were going to replace your substrate, this would be the best time to do so. Put the water you took out back in then place the liverock back in. You might want to reacclimate your livestock to the tank before putting them in, but this probably wont be that nessecary.

Any skimmer you'll find in the $50-100 dollar range is more of a gimmick than a true workhorse. Seaclones can work, but usually require mods to even get them to do much. Also these already cost over $100. It might seem expensive, but it's well worth it. I am not currently running a skimmer on my 20 gallon as im moving to a larger system, but I think having the very fine, sugar sized substrate help keep my ammonia at zero by not allowing detious to become trapped. If you changed out your substrate and vaccumed out any bits of detrious you could see when you did water changes, you should be able to keep your ammonia at 0 untill you save enough up to get a good skimmer, if you so choose. Another option is to look around on forums for people selling used equipment. Not to steal this sites thunder or anything, but over at reefcentral.com, they have a forum for selling and trading equipment. Aqua C remora's go for $100-130 shipped to your location all the time.