Zoreta

I have a new little tank that is either cycled or near the end of cycling, but it has come to my attention that my UGF is a time bomb. Is there a cheap, good quality filter available for a 5 gal tank? There isn't anything living in the tank, and I have an established 20 gal I can snitch some gravel from, so a mini-cycle won't be anything to fear.

equipment in tank: an elite 50 watt heater (rated for 10 gal)
maintenance: a weekly water change and gravel vacuum is possible- been cycling with flake food and gravel from the established 20 gal tank.

cerianthus

To make sure, do ammonia and nitrite test every few days. As far as filter for 5 Gal. i used to use Whisper Jr or Millennium 1000 for S/W 5-1/2 G Hex Nano Reef. If no room for HOB, try internal filtre wjich will give enough filtration for 5G. Whisper used to make such filter, and it took Jr. Bio-Bag.

Zoreta

The test, for the last two days, has shown low levels of nitrite and nitrate. Ammonia is 0. The nitrite is lower today than yesterday, so it should be completely done fairly soon.

An HOB would be a bit big- the tank itself is only 14.5 inch long and 8.5 wide.