My 33g AIO reef

[Corbin]

Its doing good, added some more snails to help with the diatoms and algae.
but im really confused. i have no Phosphates,ammonia 0, nitrate/ite are both 0, or 0.5. pH 8. calcium is getting back down to the mid 400s
so not sure why im getting so much algae, i bearly run all 4 T5s all day anyways, i guess it could just be still new.. only a couple months in. LR was from active tanks though.
And another weird thing, i tested the KH And GH today the KH was 12/214ppm, but the GH was unmessurable, 12 drops is the most on the API chart, i added 30, and it wasnt even about to change color, any ideas?