rio 40 $12
airline tubing $2
empty water bottle
leftover eggcrate + leftover super glue
chopped up media bag or cheese cloth
1 rubber band
water is pumped through the airline tube by the small rio. up to an upside down water bottle filled with phosgaurd, held in the bottle by the media bag piece +rubber band. gravity does the rest.
but like they all said this is just a supplemental tool. (as you can tell by the piece of algae that managed to creep into my reactor, oh boy)