Cyano or something else

[reeflife3]

Hello everyone

This is my 15 gallon IM Aio, I thought I had cyano outbreak but after 2 rounds of chemiclean it’s still there. It’s a deep red or brownish color, no air bubbles in it and it’s sways it the flow. Yesterday I did a 4 gallon water change and vacuumed most of it out and today it’s back again

Po4 - .004
No3 - 20
Alk - 6.8
Salt pro reef tropic marine
No dosing just .30 water change daily via apex dose

Any help would be greatly appreciated

 

[resortez]

Looks like dinoflagellates, there must be a high source of a phosphorus compound. Would help others with troubleshooting the problem if you can share parameter numbers, husbandry practices, inhabitants, any new/recent additions or changes, any little detail will help in drafting a solution.