Brown Gunk Marquis Epic

[matty44]

Hey guys, we've had our hot tub for about a month now and the water has been pretty good so far (no smell, nice and clear, aside from that occasional oily bubbles when we are in it - which i assume are from some residual skin lotion?). BUT, occasionally we get this brown gunk around the water line at certain places in the tub. Its not everywhere, but its gross and unsightly. Any thoughts on what this is and how to prevent it? Thanks!

Matty

[Greenhorn]

Is this a brand new tub, like one month old?

If it is only one month old, that is the gunk coming off of your bathers, I would guess. I have been using a hot tub for a few weeks now. We keep it as clean as we can. If I see a scum line forming, I clean it. We had a hot tub party a week ago, and the next morning we had a dandy scum line already.

I would decontaminate your tub, even if new, and start fresh.

[chem geek]

Could be biofilms along with greases/oils from manufacturing or bather waste. You can use Ahh-Some to help remove it if the spa has never been decontaminated. After that, you should be able to keep things in check by keeping a proper disinfectant level at all times. Some scum above the water line may still form from skin oils or lotions which can be minimized by getting into the spa clean or by using enzyme products.

[PreservedSwine]

Are you, by any chance, using a chlorine free biguanide, like baqua-spa, or an equivalent? That's what it looks like to me.

[Cooper772]

This maybe what PreservedSwine is referring to, the few times I have used a product to make water clear I have had gunk like that at the water line. Can't remember the name of the product but best I understand about how it works is that it coagulates what ever is making your water cloudy so then the filter will catch it. Have you used anything like that to clear cloudy water?

[PreservedSwine]

A biguaninde is a chlorine and halogen free sanitizer- they work quite differently than chlorine an bromine, or MPS. They don't actually oxidize the waste pathogens- they simply explode, and the filter must remove all the gunk. The product is very popular in some areas, very expensive, and a nightmare if it comes in contact with chlorine. It also does a remarkable job a creating a scum line much like the one pictured.