Greenish water in our bromine spa

[ladyinthewater]

Hi everyone!

Been lurking quite a while since my husband and I picked up our hot tub a few months back and have appreciated all the knowledge folks have shared. I'm now trying to be a responsible spa owner and do good upkeep, regular testing & cleaning, and so on, but there is a lot to learn!

The situation: we bought a used ThermoSpa Atlantis around Thanksgiving. It's not perfect (broken jets, busted light, and definitely an older model) but it's served us just fine and we plan to get it serviced properly once it gets warmer outside.

We have used bromine from the start. We're on our second fill now, since the first go-round was full of bad chemistry errors and general noobishness so we decided to start fresh. On this fill I added sodium bromide (99%) to establish the bank (don't remember how much, but followed the directions on the bottle) and then tablets in the floater which we keep cranked pretty open. I initially didn't realize how much I'd need to shock for our usage level (an hour 4-5 times per week with at least one, sometimes both of us--look, it's lockdown and we're bored!  ) so there may have been a few weeks when the water wasn't shocked often enough.

Anyway, now the water is green! Not bright emerald, but definitely more than just the blue of the plastic shell showing through. No slime or brown crud or anything else suspect. (We use the tub at night and the tub light is broken so I didn't notice until I went out in the daylight.)

I finally upgraded from test strips to a Taylor kit and did the tests. Yesterday, bromine was undetectably low (uh oh), pH was at 8 (or higher), TA 200, CH 220. I added about 3.5 oz of sodium bisulfate 93.5% and that got the pH down to 7.4 and TA to 150. I then shocked with MPS. I also gave the filters a good rinse during the day.

This morning, the water is still definitely greenish (didn't expect a change, of course). First test, bromine was at 9 ppm, pH had spiked back up to above 8, TA 175, CH 200. The higher pH might be from the shock, but since I wanted to bring TA down anyway I added .75 oz of sodium bisulfate 93.5% and that brought the pH to 7.2 and TA to 125 (better!) but left the bromine down at 4 ppm (not as good). I then added 3 oz of MPS and re-checked after letting it circulate for about 45 minutes. Currently bromine is at about 20 ppm, pH 7.6, TA 150.

My question is: is there any hope of getting this batch of water clear (and safe) again? I was thinking enough shocking to let the sanitizer do its thing would clear it up, but now I'm not so sure. I also can't figure out why the TA is so high. I know copper in the water can cause a greenish tint but I don't have the reagents to test for copper and I don't know where copper would have come from--our pipes? (We did top off the tub when the water got low with bucketsful from our work sink since the hose is off for the winter.)

We'll have to change out the water soon anyway so it's not the end of the world, but I'd be eager to know what the culprit is and what I can do to prevent it. Again, very much appreciate any help anyone can share!!