Under gravel filter help?

Em is 100% correct. Under gravel filters are terrible. Invest in a good 3-stage power filter and you'll have to do less work to keep your tank clean. Plus, youyourr fish will be happy and healthy.

I like the Aqua Clear filters too. Check them out on Amazon.com. Good reviews and prices. Fluval C series filters are awesome too.

There should be a filter in the pump section. The water going through the gravel is collected and sent to the pump. Find the name and model # of the filter and ask someone at a local pet store. They can also reccomend an algacide and water clarifier. Take a sample of your water with you in a clean container. Most places dealing with fish will check your sample and reccomend the neccesary products for water ph and alkalinity. Also, make sure you vacuum the bottom of your tank weekly depending on how many fish you have.

Under gravel filters tend to turn the whole tank bottom into a filter. For that to happen takes quite some time. They are not necessarily bad.

Undergravel filters really just suck. You need a real filter, a HOB or canister filter is your best bet. :) You didn't do anything wrong with the undergravel filter, but you WILL need to clean the water really often until you get a better filter. HOB filters are pretty cheap, you can find them for like $10 at walmart, although AquaClear makes the best HOBs in my opinion. :)