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Can’t keep FC in hot tub.

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First time hot tub owner. Just refilled a week ago, FC goes from 2-3ppm when added to zero, PH keeps rising within 24 hours. Pool store found high phosphates in hot tub and tap water. Rinsed filter, adjusted PH, added chlorine (sodium hypochlorite ), then added phosphate remover per directions, which stated 32oz per 10k gals, which would be 1oz per 312.5 gals, correct? Hot tub is 330gal, added accordingly. 24 hours later, no FC, PH higher (7.4 up to 7.8), and phosphate level coming up the same dark blue in a pillow test. Using Taylor test kit for tests. What am I doing wrong, or should I wait longer for phosphate remover to work? Water has been crystal clear since fresh fill, I refilled it originally because it got cloudy. Purged with Ahhsome before refill. Need some advice or answers, getting frustrated! At present PH 7.7, TA 60, CH 150, CYA below 30.

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It’s a Mira hot tub, 110 volt. When I went back to the store it was purchased from they looked it up and said it was a Dynasty Spa? I would guess that’s the pump equipment, it was a filter related question.

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When chlorine combines with contaminants it does not disappear, it becomes chloramines, or combined chlorine, which is readable with a total chlorine test. Total chlorine is the sum of free chlorine and combined chlorine. Do a total chlorine test to determine if the chlorine is combining. If so, there are contaminants in the water.

From my understanding it is often necessary to purge with Ahh-Some several times to eliminate biofilm. This could be the cause of your chlorine loss.

@dlleno, @waterbear, @castletonia, any thoughts?

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I added sodium hypochlorite 3hours ago, brought it up to 5ppm. Just tested, Free and Total are both at 5, so CC is 0. I will test again in the morning.

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Post a pic of the equipment area.

Your chlorine is combining, which means organic contaminants, but then it is burning off the cc, which suggests some type of oxidation such as ozone or mps (non-chlorine shock).

Was the cover on? Is it in the sunlight?

@waterbear, @Pool Clown, any ideas?

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To the top right there is a red mazzei injector with a small tube coming off the side barb. Where does that tube go?

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Goes into a junction(or Union), two ends coming off that go nowhere, a line to the left into the insulation, line to the right down around into the pump

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It goes somewhere, you just can't see where. That red thing is the ozone injector, and I suspect that there is an ozone generator in there somewhere. That would explain everything except the cc, which could be remaining biofilm in the pipes. It often takes several treatments of Ahh-Some to eliminate it all.

New tubs are wet tested then wrapped up and stored for unknown durations before shipping across country to your dealer then on to you. I have seen some seriously nasty crud come out of new spas setting up for showroom displays and on deliveries. I would purge repeatedly until no new stuff comes up in the foam. Follow the directions.

@Ahhsomeguy, any suggestions?

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This is really frustrating. Can’t trust the pool store advice. Would complaining to the Hot Tub Store accomplish anything? I’ve already drained it twice since March. My only recourse is to purge and drain again? 

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Oh, it's even worse, as there is no guarantee that this will solve the issue. I am just making suggestions based on my 25 years in the field fixing them.

The spa store has no control over what the manufacturer does and usually doesn't have the means to fill and purge every tub that goes through their store. And there isn't much the manufacturer can do as they have to test the spas to ensure there are no leaks. Water sitting in pipes will grow whatever airborne pathogens make it into there.

The pool store generally deals with pools. Spas are a whole different animal. 

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They are an option. They are often tucked in a corner or the backside of a frame piece. They could be nearly as large as a shoebox or small as a deck of cards. But it will have the other end of the small hose going to it, as well as an electric cord. 

Ozone is an oxidizer and will burn off cc and then fc. It is the most likely cause of your cc being so low, but there is some organic contaminant in the water combining with your fc to deplete it. Phosphates could do this, but so could biofilm, or bathers, or a contaminant buildup in the water. Possibly even phosphate remover, I am not sure. 

I would purge until there is no new crud coming out. Drain and refill, add phosphate remover, and go from there.

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