I have a 20 gal that's still cycling. It lost around an inch of water from top maybe from evaporation, water tests. I wanted to find out if I can replenish it? If not, will it affect the performance of my HOB filters (Penguin 100 & 200). This is a fishless cycle, by the way. It's just that I can hear the water dripping from the filter and it can get pretty loud. Thanks!!

By all means add more water. Make sure you treat it with dechlorinator or what ever you have judged you needed to do when you started the tank up. You are building a colony of bacteria to cycle the tank, but those bacteria are going to be residing in the filters of those wonderful Penquin filters, not in the water. Having water disappear is no problem. It has evaporated.

Top it off! And happy cycling!

Thanks, Daryl!!! Am sooo eager to finish cycling so I can get