Thanks for the great info on this site!
I am very frustrated with my spa. It is an Arctic Spa with a SWG. The SWG stopped working last summer and was replaced. We have been having problems with a smell and brown gunk (algae I'm assuming) ever since. It seems like we can't get fully rid of it. I did a spa decontamination by putting in the solution to clean out the pipes, drained the water removed filter. New water and got the FC level up to 100 and left that overnight. Drained, refilled and put in new filter and salt. I have been testing the water daily, but only with the strips because I am waiting for my test kit to arrive. One week later I still have brown stuff growing and my brand new filter is all brown and gross looking!!!