Okay so I've been using this KOIKA OBIO stuff for about two weeks now in my 50-gallon community tank. Here's the real tea:

First impression? The bottle is TINY. Like, I almost laughed when it arrived. But hey, good things come in small packages right?

The water clarity improved within like 12 hours - no joke! My normally cloudy tank actually started looking Instagram-worthy. My neon tetras seem to be more active too, swimming around like they got a caffeine boost.

Smell test? Passed with flying colors. Before this, my tank had that... you know... fishy smell (duh). Now it just smells like... water? Which is weird but good weird.

BUT here's the thing - it didn't do much for my cycling issues when I set up a new betta tank last week. Had to go old school with that one.

My guppies are popping out babies like crazy though! Not sure if that's the product or just my guppies being... well, guppies.

Would I buy again? Probably yeah. It's not magic but it does what it says on the bottle (mostly). Just wish they'd make bigger sizes!