Keeping Drip Lines Clean

Hey all got a ? about keeping my drip lines and emitters clog free. I have a gravity feed set up from my rain barrels to my GH. During the summer I water my 100 gal pots about every 3 to 5 days. The water setting in the tubing is growing some shit that keeps slowing down my emitters.
What can I safely add to my system to eliminate this buildup of algae and not affect the girls?
Thx for lookin...SD

remove algue from barrel in the first place

is a start

ensure light don't get in at all even the tubes

enlarge emitters with a small screwdriver?

check system daily

above all water more often but less volume

maybe a small piss every 24H

a bigtime clean with 15% bleach at harvest

and

have you ever had your rain water lab tested $15-$50 pa

good luck

Thanks for the reply all are very good ideas. Yeah my rain barrels are white so that kinda fucks me right there. I was wondering if there was some sort of organic substance used by hydro growers to keep scum down that could be used in irr water for soil as well. At least adding something to the last couple gallons of water that would set in the drip lines. Haven't had the rain water tested, not sure why I would.