Help... (my tank needs some TLC)

That’s trippy, never seen or used one of those, but IMO if you have proper circulation and don’t over feed, that kind of gravel cleaning isn’t necessary. I never clean my gravel and I can stir it up and nearly nothing comes up
Will a sponge filter help with it?
 
Will a sponge filter help with it?
Depends on the flow, on a 40b I would run something rated for a 75g or bigger. Whether it’s a powerhead or an HOB with sponges in it, the result should be the same. When you feed or your fish poop, watch and see if it sinks or gets caught in a current. That should tell you if your circulation is adequate
 
AquariaCentral.com