holycow! after i search around and found out that Bushy Nose Pleco, also known as the Bristlenose Pleco is the killer! and i've been looking for it a while, since most of my LFS sold out....... but guess what, i finally got 1 yesterday, 4" long and it costs around $7. and man oh man, well worth the money. 90% of my 30g tank's algae gone within 12 hours. amazing! recommand to anyone has big algae problem like me