Need help with Cl and CYA levels

[SunOfAtom]

Hello,

I am a new hot tub owner and I am slowly learning the intricacies of spa chemistry. I have read the stickies which are incredibly helpful, but I could still use some advice. The hot tub is 280gal at 100°F. The water is clear and feels fine, but I just tested using the Taylor FAS-DPD kit and it appears that my CYA has become way too high. Here are the current values:
pH: 7.4
TA: 70ppm
CH: 220ppm
FC: 8.5
CC: 1.5
CYA: ~140ppm (mixed with half fresh water, tested at around 70ppm)

It is entirely possible that there is some user error with the testing procedure, so please keep that in mind. First of all, shouldn't CC be higher than FC? If I drain half the tub to get CYA levels down, how do I bring up Cl without adding CYA? I have a couple different types of chlorine powder, but I assume they both have CYA. Do I run to the store and get some liquid chlorine?

Thanks!
Dave

 

[AftonJeeper]

Yes, You will need to run and pick up some liquid chlorine. In the sticky you should only use dichlor until your CYA is about 30 then switch to liquid.

CC should be below FC and ideally below 1. Maintain a FC according to this chart: [FC/CYA][/FC/CYA]

Good luck!

 

[SunOfAtom]

Excellent, thank you for the info. I ended up taking a water sample to the local pool/spa store and had them test it. It turns out that the levels were all great (FC around 3.5, CYA around 50). Apparently I just don't understand how to use this new testing kit. Fortunately I had not started draining the tub or anything like that. The shop said they have a simpler testing kit and some great test strips coming in soon, so I may see if I have better luck with them.

Thanks again,
Dave

 

[mknauss]

Welcome to the forum!

If you read through this forum a little, you will notice that we do not recognize Pool Store tests as accurate. You have a quality test kit, it is your water your managing, and you will test it far more accurately than any Pool store.

Good luck.