As someone who's struggled with algae-filled koi ponds for years, I was skeptical but hopeful when trying AquaDoc's Pond Clarifier. The promise of a natural, fish-friendly solution sounded too good to be true - but after three weeks of testing, I'm pleasantly surprised!

The first thing I noticed was how easy it was to use. Just measure based on your pond size (my 1,200-gallon pond needed about 1/8th of the bottle) and pour directly into the water. Within 48 hours, I could already see the water clearing up significantly.

What impressed me most was how it handled stubborn algae on the pond liner. Previous chemical treatments left white residue or required scrubbing, but AquaDoc's enzyme formula gently broke down the gunk. My koi actually seemed more active afterward - no signs of stress!

However, it's not perfect. Like some reviewers noted, extremely murky ponds might need multiple treatments or mechanical cleaning first. My neighbor tried it on his neglected 500-gallon pond and saw minimal improvement until he manually removed debris.

The concentration is fantastic - one bottle lasts ages for small ponds. But beware: overdosing can harm fish if water temperatures exceed 80°F (as warned on the label). I tested this carefully in a separate container first.

For maintenance, I now use half doses weekly which keeps my pond crystal clear without constant skimming. It's saved me hours of manual cleaning while keeping my fish healthier than harsh algaecides ever did.

Bottom line? Works brilliantly when used correctly on moderately troubled ponds. May need supplemental cleaning for severe cases, but hands-down the safest effective clarifier I've tried for stocked water gardens.