Need advise

[wickedfrags]

If it is an old/second hand piece of liverock simply replace it would be most cost effective. If it is a new piece of liverock which has never had algae, check the TDS of your RO/DI unit.

Also, should a hobbyist or LFS have a sea hare for rent, you could use it for a day or two as they are historically known to eat hair algae.

[revgeoff]

Sea hares are great at getting rid of hair algae (at least mine are). The only problem is that powerheads like to eat sea hares....actually, they LOVE to eat sea hares (oh poor flopsy I hardly knew you).