Help needed for a few ongoing problems

[Susanj]

I have a few ongoing problems with my spa. It’s an acrylic shell , 375 gallons and we use the 3 step bromide system. 

 

1.After one use I can get a bromine reading of 0 and I’ve even waited overnight to see if the floater would bring it up like I expect it to , but no. I have to shock.  This doesn’t seem right.

 

2. I have trouble getting alkalinity over 40 especially without pH going too high . I read somewhere that even 40-50 can be ok? 

 

3. Lately I will vacuum my spa , then not use it and the next morning there is more stuff to be vacuumed up. It feels gritty like sand so I don't think it's algae which I was first worried about.  We have 3 filters that we rotate and they are rinsed after each stay (this is in a vacation rental) and deep cleaned monthly. Could they be wearing out? Three filters for 3 years....is 1 year about the average life span?

TIA