Algae

Question
I have 2 community fish tanks, 110 and 20 gallon. In the 20 gallon I have alot of hair algae growing on everything and in the 110 I have algae growing pretty significantly on the glass. I am away for college and my siblings don't clean the tanks that often, but they have never gone more than a couple weeks without a water change. I have 1 pleco in the 20 gallon and 3 in the 110, all various bristlenose species. Is there any option to rid it besides scraping(which takes FOREVER) or expensive algae chemicals?
Thanks, Jarrod

Answer
Jarrod,

I will take a stab in the dark and say they might be leaving the light on too long. the aquarium light should be on no longer than 9 hours a day. Once the algae has started it is hard to get rid of it without using a algae removing chemical. If you do not want to use one then your best option is scraping it out.