Hello! Hope everyone is well.
I recently emptied my spa due to cloudy water that appeared to have a type of film on the top of it. It was due to be changed anyway, so I emptied and refilled my spa.
Now, within a week, I'm noticing the cloudiness and film again. I guess it's film, it's all broken up (due to the jets running when I add my chems.) but it does appear to be some sort of film.
I've not had this problem in the 5 years I've owned the spa. I had white mold a couple of years ago when I used Baqua Spa, but now I'm on Chlorine and silver ion and an ozonator, and haven't had any problems like this to date with Chlorine.
(I tested ph and Alk last night and I was just slightly low on each (110 Alkalinity and 7.4 pH), so I added chems. to rebalance that. My Chlorine is always close to zero when I check, so I added 1 tsp Chlorine as usual.)
Any ideas what this could be?
thanks!

Sounds like algae if your chlorine is always close to zero when you test. However, if you post the rest of the number we can help further. Specifically, CH, CC or TC and FC. Also, are you saying that your TA was low and was reading 110. This is not a low number and is in fact pretty high. Should be around 60 to 80. Anyways, post a full set of numbers so we can help out.

I agree with the TA level too high for a tub - target 50-60 to keep PH drift rate down while adjusting CH to keep water in balance. Also, what is your Chlorine source? Dichlor, bleach, etc?
Your FC should not be eaten up so quickly which means either CYA is too high (exclusively using dichlor) for the chlorine to be effective or you may have something eating the contaminants. Whats your CC or spent FC.
When you drain and refill do you super-flush and/or de-conaminate the tub before draining?
Lastly - how often do you add the chlorine and in what quantities for a 355 gal tub?
Barry