If I let the FC level in my hot tub go to zero for a couple days, the water will become cloudy and become even cloudier very quickly (like a bacterial bloom). No problem - I just keep adding a bit of bleach every couple days and a bit more bleach after every use, and this keeps it in check.
However, just recently, the water turned a bit cloudy and has stayed a bit cloudy, despite shocking with bleach and even using a flocculant (Bright & Clear). Over the past 3 days, it has remained cloudy, despite my best efforts.
I'm going to drain and refill, but just wanted to see if anyone had any thoughts about this. The water is about 5 months old. I know this is longer than recommended, but the usage has not been that high. I have tracked bather hours pretty closely, and according to guidelines and calculations, we should still be ok. But, in any case, maybe the water is just old, TDS is too high, or whatever, and therefore, it just won't get crystal clear with any chemical additions anymore.
The other alternative explanation is a bit stranger. I brewed beer a week or so ago, and as part of that process, I run water through the hose and into a copper coil which is immersed in the proto-beer to cool it before fermentation. The water coming out of the copper coil is hot, so I figured, why waste it? I let the hot water flow into the hot tub until it was at max fill, then let the rest go into the yard. So is it possible that enough copper was released from the inside of this coiled tubing to discolor the hot tub water? Could the copper ions be reacting with something else in the water to cause this greenish cloudiness? It seems very unlikely to me, but thought I better ask...