Hi all, first time poster. So I had a hot tub growing up, but never really took part in the maintenance being a kid (although drainage and scrubbing was all on me 👌). That led to me wanting one again as an adult. I don't have a lot of room and I rent, so I found an mspa b141 "4 person" hot tub. (quotes because I can't even figure out how 4 people can actually fit it in! Not just space wise, the water almost overflows with 3!). That is an inflatable Hot tub for those wondering. So like most people, learning how to deal with balancing and water chemistry isn't instant, but through research and trial/error, I got the hang of it. I test my water fairly religiously and everytime before I go in, and manually clean debris + adjust chemistry as needed. The tub is apparently around 700L capacity. The last week or so however, I've been having a weird issue with free chlorine spiking. I use an aquachek digital tester and a standard test kit (adding chemicals to sample and comparing colors) as backup. The readings are accurate. I use chlorine tabs that are stabilized and they have worked perfectly, and the dosage is right. My ph is usually balanced, but tends to push towards the high 6s before I treat. Without adding a different dose or changing anything, I started getting free chlorine readings in the 7-9.8 range! Ph usually between 6.9-7.7, alkalinity around 100-130. I can bring it down by removing the chlorine tab floater, adding water, leaving it open for the sun etc.... But as soon as I put the chlorine back in, it will climb to those high levels within the day. I've shocked it with non chlorine shock which does not change the behaviour, and tried to put a less than recommended dose in. So I'm at a confused point here. This is free chlorine to be clear, and the numbers are apparently correct.