That should help pull the Phosphate out of the water. Not really familiar with Rowaphos, but have heard others use it on this site.
With the existing algea, I would suck out the Cyano
with airline tubing siphon, and replace the water with new. Some people like to strain it and put it back, but IMO
, you can't strain it all out, why bother. The hair algea, try to manually pull out what you can. Any remaining hair, maybe a crab or 2. The crabs help get rid of the hair algea but the nutrients from the algea are still in the tank, now as crab turd. So the crab takes care of the symptom, but actually adds to the overall problem of too many nutrients. The best way to limit the nutrients is careful feeding, and regular water changes. Limiting what goes in the tank and regularly removing what is in the tank is the best way to avoid algea problems.
Beyond this, look for algea turf scrubber on this site. This is a way to use algea against itself, and from what I'm learning it works better than a refugium at exporting nutrients.
Good luck with your tank!