@GixxGrows sounds like you need a bigger air pump for your stone. A 50 gallon pump should do.
@Mrb53004 has a good option too of adding a recirculating water pump.
With algae though even if there’s an air stone or a recirculating pump algae can still build up. You should clean everything thoroughly and when you replace the water in your reservoir make sure you filter it first to remove any algae that might be in it and make sure you have a top on to keep it covered to keep algae from getting in it again.
Another option is to add some organic algaecide to your reservoir. They make some specifically for cannabis growing and Hydroponics. I wouldn’t use one of the pool ones.
If that’s out of your budget some apple cider vinegar will work and also give you a slight nutrient boost but be careful using it as it can decrease ph. Just no more than one tbsp per gallon of water. I use about 2 tsp per gallon myself and it’s enough to work as a fungicide, algaecide, antimicrobial, and as a micro nutrient booster.
Another cheap and effective preventative is to throw a few pre 1982 pennies in there or a piece of copper pipe. Copper is a natural algaecide and it won’t hurt plants since it’s also a beneficial micro nutrient.