Horizon Ventures 2-Pack Pool/Spa Scum Eliminating Reusable Scum Ball

These seem to work. You can see the oil gathering on the sponge after it has been in your tub for a while. Given the price, I think they're worth buying. They certainly do no harm, and at least appear to be gathering up oil and grime that isn't being picked up elsewhere. I regard them as a weapon in my overall cleaning arsenal.

fun, but dont squeeze the water out of them they take forever to spring back into shape

Previously had a floating sponge that did the trick but wore out after many washes. Bought these to do same job, but they have absolutely no effect. I still get a scum line and they collect nothing. Waste of money

Anything that keeps the oily scumm off the top of the water must be a good thing. Only problem is it keeps getting sucked into the skimmer!

Can't complain, does what is says. Within a week of putting it in the hot tub it had a ring of green around it, which to me means it must be working! Cheapest I've seen too.

Did what it said on the tin!

Don't have scrum so presumably theory make a contribution to the cleanliness of the tub.

Best ones we have found