Hose filters help - but don't 'cure'. We used the Slime Bag too (captures particles as small as 1 micron).

What I'm seeing everyone say when you have to keep CL levels very low for an extended period of time, is to also use polyquat 60 algaecide during that period.

It goes by diff names (mine is black algae treatment), but look for the main ingredient of poly-something-something-ethylene 60% (not sure where the "quat" comes in).

Good luck to you!! I was SO ready to dump our 13.5+ gal swimming pool before we decided to try the homemade filter - and it's been a savior!

Keep posting!