New tub, first numbers

[Laenini]

The new tub arrived and its up and running. I just checked my first set of numbers and here they are:

pH = 7.8
FC = 1.5
CC = 0.5
TC = 2.0
TA = 260
CH = 320
CYA = 25

Now, before any of you tell me that I am crazy and that I need to go check those numbers again, I should explain that we used 1/2 fresh tap water and 1/2 water from my pool to fill the tub, so that is why there is already CYA and chlorine showing up.

I did a quick check of my pool water and its readings tonight are:
FC = 6.0
CC = 0

So, my first goal is to adjust the TA, correct? Its a 500 gal tub so I am going to add a total of 5 oz of MA (diluted and as 2.5 oz additions) and then turn all the jets on. Then I recheck in 30 min, right?

Any thoughts too on why my pool tests negative for CC but I'm finding them right away in the tub? Should I shock just to be safe?

 

[PaulR]

You're on the right track for lowering TA. Because of the high CH and the high temp in the spa, you'll want to keep pH and TA low-ish in the long run.

I always get some CC in the spa and rarely in the pool. I wouldn't worry about it as long as it's 0.5 or less.
--paulr

 

[chem geek]

And I would especially not worry about the CC if you see it high after a soak -- that is to be expected. It's the CC level before the next soak that is relevant and as Paul says if it's <= 0.5 ppm I wouldn't worry about it.