Robyn

That's a good suggestion. Thanks.

When I tested last night, it looked to be 80 ppm nitrates. That was after three significant water changes over the past month. A few weeks ago, I also "hotrodded" my HOB filter with many of the products from the Coop, as well as adding a bag of Purigen to the filter. I also added a new Coop sponge filter to one corner. The nitrates went down somewhat from when I tested them a month ago, but I was hoping they would have significantly dropped. I will admit that up until recently, I was woefully behind in techniques and technology, and I had been neglecting regular water changes, but I'm trying to catch up now. At this point, the water is crystal clear, and the fish seem healthy and active, but the nitrates are still high.

Has anyone tried the EA Premium Nitrate Reducer Filter Pad? Will it work, in general? And, more specifically, will it work in a hang-on-back filter?

That looks very similar to what I want to do.

The medium sponges are thinner and less obtrusive. I was thinking of maybe stacking two of those.

I'd like to see a video on the proper way to stack sponge filters, including where to place the air stone.

I know this is something that people don’t normally do. But I have some extra media bags and bio rings that I want to put to use. I was thinking of putting one or more bags of rings inside the tank hidden in the gravel as much as possible. I was thinking of putting one under a sponge filter or under the spot where HOB filter flows into the back of the tank. I want to hide them as much as I can. Would this provide any benefit, or would it be a waste of time.