500 gallon hot tub. Water was last changed 3rd week of May (5 months after initial fill). It's only been my husband and myself in and never with suits on. In the last month or so, we're getting "foam" in the water in the corners depending on which jets are on. The water is fizzy but I understand that's normal and can get worse as the water ages. This foam doesn't happen with just the jets on, only when the air is on too. We scoop it out as much as we can but it's getting annoying. We just changed the filters today and it seemed worse tonite so my suspicion is they filters weren't rinsed well enough but this isn't a soap film... it leaves no scum line or anything and it's not slippery. When the air gets shut off, the bubbles go away right away. And with the jets off, the water is crystal clear and sparkles.
We use the dichlor then bleach method. Last time around we had a scum bug in the water but we've tossed it because it was getting too scummy but have another one on order. We're having friends over this weekend and I'd rather not dump the water before then (plan to dump it sometime after before we get into too cold here in Northeast PA).
Our weekly test results were:
CH: 90 (well water, never had to take the calcium up before and since it doesn't seem to be a soap type foam, I'm wondering if we should mess with it)
FC: 2.4 (before the soak tonite)
Wondering if anyone has any ideas.