I havn't been here for a while but here is what I found.
I haven't been in the tub lately due to time spent with photography business. I went three weeks without even opening the tub. I use frog minerals with manual dichlor and two - one hour filter cycles per day. The tub got cloudy but I recovered it with a mild shock. I took a dip the next morning, added a bit of dichlor and closed it up. Four weeks later, I opened it up again and the water turned on my - really bad. It was to cold for a dump and fill so I tried to recover it. 24 hours later, it was still cloudy and a bit discoloured. I was going to dump the following weekend but when I opened it - crystal clear water. I added a bit of dichlor and it was good to go.
The bottom line, I found that wy water used to turn after three days with 0 ppm dichlor, With the mierals, I get weeks now. If you use your spa daily, don't bother with it. If your like me, then consider trying it.
Steve