The thing with BGA or cyanobacteria is that- unless you fix the root cause it will keep coming back-
BGA doesn't like- high nitrate (10-20ppm), low pH, high CO2 levels, low organics and high/strong water flow.
By tearing down the tank or using antibiotic or algaecides you have to re-start the cycle...
You could also try removing the livestock and doing a total blackout for 4 days-I wouldn't do it with livestock in a small tank....too risky for the animals IMO
Note: if you opt for a tear down-boiling is not really needed especially any rocks as this can be dangerous to boil or bake rocks due to risk of explosions....just saying.........
Correct the cause of the BGA by removing it manually and stay on top of water changes/vacuuming daily to keep organic in check, increase water movement.
Also, aquatic plants-Elgeria densa and Ceratophyllum demersum are reported to help prevent BGA by secreting a natural antibiotic substance.