I don't know how much space you have but you can add a sump if you use an overflow filter system. To control your water parameters and cyano I would reduce your feeding just a bit and reduce your lighting for a few weeks till the cyano dies off. I sounds like you could also use a little skimmer too.
Smaller tanks are always the most difficult to care for. The more water you have the easier it is to control water parameters.
I have a 40 gallon breeder with a lot of live rock and corals with a 10 gallon sump, Prizm skimmer, and 1 Chemipure pouch. I rarely do water changes, I just add calcium, trace minerals and monitor my Ph, Alkalinity, Calcium, and Phosphates. Nitrates and Nitrite are never a problem with all the live rock I have.
Just in case you do have an overfeeding problem (Nitrates/Phosphates), making sure you have enough scavengers to clean up any excess can help a great deal. Good Luck!