You dont need 60 snails in an empty tank. All that does is add more polution ot the tank.
The CuC is needed to trim down the excess waste that fish and uneaten food leave behind.I dont seen anything in that tank.
Too much, and they just compete for the resources with each other. Honestly, they really dont do that great of a job cleaning up excess hair algae.
Instead they just throw your readings off. It is a sad myth that people get these over sized CuC based on the 1 invert per gallon theory that floats around.
To put it in perspective my 160g SPS system has a dozen fish in it, to counter thier waste I have maybe 20-25 snails and hermits.
And I typicly feed about 1 cubes worth of food a day.
Hair algae is common to a new tank that is establishing itself, expect to see these outbreaks the first year, the first few will get worse than the previous.
Then suddenly it will die off, and each time it will be less than the previous, and eventually it will only happen in small patches that can be trimmed manually with just a couple minutes effort every few weeks. From the looks of it, a $20 sea hare will pick that tank clean in less than 2 weeks, then you can give it to someone else local.
Reduced lighting will also help stem the growth, 8-10 hours a day is the most you need if your doing corals. If your not, then you dont need any light. Fish are fine with a lit room.
Since I dont even see that, you can just shut off the tanks light altogether till you have some livestock or corals introduced.
Hope this helps.