We've had challenges since we started this tank for a few months now

I have 20 opae ula shrimp, however over the past few weeks our tank has gotten increasingly foggy and we had some black algae growth. I cut down on the light time and even given the tank a few days without light to help eliminate the black algae. It seems to have done the trick, however now we have a very foggy tank.
In addition, about 10-12 of our shrimp are staying huddled behind the filter together. We have a lot of algae in our tank, and with the shrimp only staying behind the filter algae is continuing to overgrow our tank.
I have read the fog could be called a bacteria bloom and that airstones can help to improve the tank clarity. I am thinking of getting some snails to help with the cleaning of the glass, but previous to getting our shrimp we had snails for about a week and they all died. I'm not sure what could be causing all the issues. Does anyone have experience with airstones? Will the snails help? We have a bunch of macroalgae that we purchased from Mustafa with our first batch of snails, however that is a dark green color and doesn't appear to have grown.
Can someone provide some suggestions of what we can do to help our tank?