This would be my suggestion given the widespread algae problem the OP currently hasThere is a less effective method without removing from rock
Turn off all flow and use a syringe with pure hydrogen peroxide and slowly slowly squirt the algae with the peroxide. As soon as it comes out it will start to dilute with sw and make the peroxide less strong. So this may take several tries. The goal is the same as using the dip. Algae reacts with hydrogen peroxide and will bubble and fizz. Then you need it to let it continue that for a few minutes and then turn on the water flow again