i have been battling with this for over a few weeks now. and the more i do to get rid of it the worse it gets i have try changeing flow if i put any more pumps in fish will be stuck to glass ...have any of you heard or used this http://www.weissorganics.com/algaemagic.html
Anywho, me personally I wouldn't use any chemicals. The algae is there because you have a build up of nutrients. Whats your test read? Nitrates and phosphate would be the culprit here. Less this is a new setup? Post your water params and a pic would be great too.
i know pic not very clear but it does look like hair algae yes sorry i keep getting them round wrong way by the time tank lights go out all sand is nearly covered