Algae ID help

[MadScientist01]

Hello, any assistance on fixing this persistent algae would be appreciated. Tank is about 6 months old no corals. 3 fish a shrimp and a snail. I have one Reefbreeders micro led lamp tank is 20 gallons. Using a marineland canister filter. Weekly 10-15% water changes with RO water from LFS. I use Red sea salt. Pictures and levels test are from today. Purple hairy algae no matter how much i try to remove it just keeps returning days later.

20 Gallon tank

Salinity-1.024 on refractometer

(API Test kit)
pH- 8.0
Ammonia- 0.25ppm
Nitrite- 0ppm
Nitrate- 2.5ppm
Phosphate-1.0ppm
Calcium- 440ppm
KH- 196.9
Copper- 0ppm

 

[EeyoreIsMySpiritAnimal]

Cyanobacteria. How much flow do you have? Cyano loves low/no flow areas

 

[EeyoreIsMySpiritAnimal]

Also, no need to test ammonia or nitrite in a cycled tank.

Your phosphates look high. API doesn't give precise levels so I recommend testing with another brand and getting an accurate value. If phos is that high (with nitrate as low as yours is), that imbalance can certainly be driving the cyano outbreak.

 

[MadScientist01]

Also, no need to test ammonia or nitrite in a cycled tank.

Your phosphates look high. API doesn't give precise levels so I recommend testing with another brand and getting an accurate value. If phos is that high (with nitrate as low as yours is), that imbalance can certainly be driving the cyano outbreak.

Ok ill throw out the API stuff and try something else but i currently have one powerhead that i got on amazon in the top right of the tank pointed towards the left side of the tank. I dont have it pointed towards the bottom because if i do that the sand will get completely pushed around and expose the glass. Not sure what the exact strength measurement of the powerhead is.