My very first tank was the biocube 32.
The best upgrades you can get is the intank filter tower insert with filter floss, mame design skimmer, and a DC pump for the noise. If you live in a hot area, that biocube lid traps heat, so I ended up getting rid of the lid and buying a better light like the AI Prime 16HD. I tried chaeto and ended up giving up. The makeshift “refugium” ends up being too tiny to be effective. Any larger designs just doesn’t get enough flow to properly grow.
If I were to start over again in a biocube, i’d likely get the nature dimensions fleece roller instead. DC pump is still a must have. Skimmer is a must have too. Stay away from the corallife skimmer. They’re pieces of junk. The mame design skimmers + eheim pumps work way better.
The tank is always the cheapest part of this hobby…