Help please algae issues

[Coralgurl]

Thank you all for the feedback and tips! I went through Mykas articles last night and will do some more reading today.

To clarify a few points....this is my 55 gl tank. Running on a canister filter, no sump. Tank is 2 years old. I have 3 power heads, one mp10, 2 koralias (4's) I believe. The mp10 is set on reef crest, placed on the end of the tank in the middle at 100%. The 2 koralias are also on the ends but pointed at the surface.

I ran out of rowaphos and been substituting gfo in the canister. I just picked up fluval phosphate media and will change out today with a water change. I've been changing 25-30 gls of water with each change, max I can do at any one time. Water changes every 2 weeks.

I only use RO water, feed frozen but thaw and rinse before using, every time.

The skimmer I added is rated to 100 gls and with 6 small fish, don't think my bioload is too much.

My parameters are as follows

Phospahates .25 API test
Nitrate 20 API test
Cal 420 elos
Alk 8 elos
Mag 1100 elos
Ph 8.1 elos

It looks like I need to increase my cuc as I don't think I have any alive in the tank.

Where the hair algae is growing is the rocks on the bottom of the tank, I can pull these out and clean as they are small.

Good starting points-I'm not sure if I can run a bio pellet reactor on this one with no sump, I've been looking around and haven't found one. Will read about other options.

Thanks again!