ID my uglies... diatoms?

[BruceLeeroy]

Tank is 10 weeks old, old school shrimp cycle, overdid the shrimp and so the uglies are bad. Ammonia is 0, nitrite 0, and embarrassingly high 50 nitrates and Phos 1.0. I’m starting a regime of 25% water changes every 2 days to get the nitrates and phosphates under control. The Chaeto I added to the refugium is turning brown and slimy so probably going to take it out until the tank is more stable. Only occupants now are some fat and happy trochus snails.
is This diatoms or cyano? It seems to be getting slowly better so not too worried I think 3 or 4 water changes should fix things on the nutrients.

 

[Miller535]

Looks like diatoms. With possibly some cyano, Very normal for a new tank. Just make sure you are using RODI water for your water change and top off