sorry, i very kia-su, using actually:
purigen + nitrate controller + Carbon + poly filter all together,
reason: only 22 gal tank, and DSB not functional yet, so resort to all these chemical filtration stuff to keep nitrates in control, my last tank had a major red slime algae bloom problem.
but this tank, so far so good, but then still cannot overload with life stock, cos nothing will help 10 fishes in a 2 ft tank !!!
dodo, algae prob may be due to phosphates too, you may need other stuff like phosguard to the rescue.
it costs abt $26 for a small bottle. let me know if anyone wants to try, I dun mind sharing out the cost proportionately depending on how much you need, as I still have 85% of the bottle left. (pm me). may give you a feel of how useful you find it before buying a whole bottle...
but i wouldn't bleach them to recycle as directed on the label..dun feel safe, just replace with new ones.