Jeff:
If you can get someone else to help you, that will be extremely useful. As Almost has said, you need to siphone algae that is released into the water.
When I had algae issue with my tank, I took out as much rocks as I could and scrubbed them good. Rocks with corals that cannot be removed from the tank, I did the following:
Get a 100micron large filter sock. Line it with filter wool. Now stick that securely into your sump. Get a long hose and get your helper to stick that into the tank and create a siphone and insert the other end into the sock with the filter wool.
Now start scrubbing and make sure the other person gets as much of the floating algae going into the hose.
Having a siphone straight into your sump means there is a continuous water flow. And since you have the filter wool and filter sock, most of the algae will be trapped.
Buy LOTS of clean up crew:
For my 47G tank I bought the following:
2 x Large Mexican Turbo Snails.
6 x Large Astrea Snails.
6 x banded Trochus snails - these are very fast moving and can right themself
6 x Red Leg Hermits
6 x Blue Leg Hermits
So basically something along those lines. You can also try urchins and a sea hare too. Or an algae blenny.
Reduce light hours to no more than 6 hours.
Use regular GFO, and replace weekly.
Water changes. Mix at least 25% of w/c a week in advance, so its fully mixed etc. And carry out at least that amount each week.
You can siphone out that amount of water whilst you are scrubbing the algae off in order to reduce any toxic effects.
Be careful with the pellets. They cause so many people STN and RTN issue. Ensure you keep your alk somewhere around 7.5dkh.
Sorry for the rant, I kind of lost track of your original question.
Hair algae can irritate SPS if they land and grow near them. Whether there is any toxic effects...I dont know.
Goodluck.