I have been lurking on this site for a while and decided to sign up recently. I am the proud new first time hot tub owner of a 2021 Nordic Spas Crown XL that only took 6 months to arrive at my house! Lol. I have been struggling with the right combination of water chemistry and have subjected myself to a few bad water situations already with itchy pock marked skin to show for it. Hence "Lab Rat" as my username. With the help of this site and 3 water changes and 3 weeks later. I think I have arrived in my happy place. Test strips are reading perfectly! I went from too much chlorine then too much bromine (smelled awful!) now I am back to chlorine after doing a deep clean jet flush that resulted in some nasty green slime left over from the factory. Spa place I bought it from never mentioned to me that it might need to be flushed first because there is always nasty Darn left over after they wet test it at the factory then it sits in there for weeks before it is delivered! They didn't do a lot of stuff that I expected. Customer service is lame across the board these days! That's when I found this site! Thanks for your continued guidance! Happy hot tubbing!