It's "okay", good for nano tanks but that's about it.
Again, 10 gallon tank with an Eheim 2213, so not very much flow at all.
I can barely get to a 1.0 drop in pH before bubbles are shooting up and out into the tank, the "turbo" wheel thing on the inside does nothing except inhibit flow - it doesn't "chop" up the bubbles at all, it doesn't even spin freely = it's seized up 3/4's of the time blocking even more flow.
The only way I could get it to stop spitting bubbles into the tank was to throttle back the filter after the reactor which increased backpressure and dissolved slightly more gas.
It's a nightmare to prime / purge the air out of for maintenance unless you completely turn it upside down (annoying).
It's quite loud for it's size - lots of sloshing and splashing noises, especially if the filter lets a little burp of air out.
For $20 I got what I was expecting I guess, so I'm not upset about it