I used to use spa perfect, then switched to another enzyme product but after a while I found I didn't need it. The first time I used it I had a huge scum line, I put the product in and in 24 hours it was gone ... I thought WOW!!!
It did seem to work but chlorine/bromine attacks the enzyme so sanitizers are somewhat less effective. I started thinking about it was a waste of money to put an enzyme product in just to have chlorine attack it.
What you may find is that as you use the tub, don't have suds in suits and become more aware of water chemistry that you don't need to use it as well.
I used to keep a bottle around "just in case" but I hadn't used it in a long while and I found that I stopped getting scum lines unless a bunch of people (teenage son and his friends) went in. I have since adopted the policy of scooping out the foam and hitting the tub with MPS. I only use the straight MPS so it works quite effectively at burning up the contaminents in the spa.
