SPA and Chlorine

[solidslush]

Hey all! I have a small spa, 175gal on a ChlorMaker drop in SWG. Something is eating through all my FC, here's my latest test numbers.

FC: 22
CC: 5
PH: 7.6
TA: 100
CH: 250
CYA: 80
Salt: 1800 (System has low salt needs)
Bor: 50

I started SLAMing a few days ago, but due to work I haven't been able to test it every few hours. I was noticing that I couldn't seem to raise my FC above around 1.5. So I tested my CC and it was high, around 4. So I started SLAMing. The CC & FC fluctuate in terms of need. I SLAM my greenish pool a week or so back and it went great, this tub not as well. It's eating something in there, but I certainly don't see it. The water is beautiful, though. I do have a 3 day weekend coming up, so maybe I can hold it at 31 for a while.

Any other advice I should be looking at?

 

[ant 83]

Replace your filter.

 

[Brian VT]

I'd bet you have biofilm established in your plumbing (and maybe the filters too).
Do an Ahh-Some treatment. Maybe more than one.

 

[solidslush]

I've ordered a new filter. One tip I've read on a forum post, that I didn't see anywhere else, is that sunlight is needed to break down high CC's. Leaving my cover off for a few hours really dropped my CCs.