The a & b is a two part additive for your tank. It boosts alkalinity and calcium. Both need to be at proper levels for your corals to do well.
There are a number of different types on the market so you can chose.
The algae growth is from too much nutrients in you tank or maybe your lighting.
Watch how much you feed and don't let your bulbs get too old.
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250 gal display tank plumbed directly to my wallet
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