Newbie 75 gallon

[Frogger]

A bristle tooth tang would be a perfect addition to the tank. Not sure your tank is mature enough to keep chaeto alive and actively growing. Try to find a clean source of different coraline algaes.

J@L sells Tiger Pods. If you can find someone with a perfectly clean tank with no bad things in it add a piece of live rock from that tank. Not sure where you are going to find that.

My small tank is pretty clean although it would be a source of cyno, diatoms, hair algae and dynos even though they are currently not visible I have had them in the past few years so they are only actively waiting for poor conditions to return to encourage their growth.

Not a big fan of hermit crabs. Water changes, water movement and a good skimmer is about all you can do. Check your source of fresh water as well, change filters add a DI Filter if you do not already have one.