# Thread: Tri-chlor pucks to raise CYA

1. ## Tri-chlor pucks to raise CYA

Hi team,

Wow, I can't believe I didn't know about this site before. I always just let my husband take care of the pool but he's working away now and I'm in charge! Time to get a better system in place. I'm currently dealing with algae (I'm sure that's what brings all newbies here!), it is grey/cloudy and seems to be dead (I am brushing every day) but my new kit is in the mail so it's hard to get exact numbers for you at the moment. I'm trying to keep my FC > 10. I've been taking samples in to the pool store but that is time consuming.

I want to make sure that once the water clears up I can keep my FC high enough and therefore I need to make sure my CYA is high enough. I usually put in 3 pucks twice/week but that clearly wasn't providing enough FC and/or CYA to keep the pool clean.

I do know that I need to get my CYA up, I think it is under 20. I would like to use up my remaining tri-chlor pucks that I have to do that instead of buying stabilizer on its own. I don't see a function in the pool calculator of how many pucks I will need though. What's the best way to figure out how many pucks to use?

2. ## Re: Tri-chlor pucks to raise CYA

If you are using 6 pucks/week, your cya is probably quite high so the chlorine is not sufficiently effective. Test your cya when you get your kit. If test shows 100, test again with half pool water, half distilled water and the full amount of reagent, then double the result to find your true cya.

3. ## Re: Tri-chlor pucks to raise CYA

You can use the "Effects of" section at the bottom of the pool calculator to figure that out. For example, with 26400 gallons, 8oz of trichlor will raise your CYA by 1.3.

If you have been using 6 of these per week, that would be adding 7.8 ppm of CYA each week. (If your pucks were not 8oz, you would need to adjust the figures.)

4. ## Re: Tri-chlor pucks to raise CYA

Thanks. I'll take it to the store tonight to get it tested. It has always been "low" according to the pool store so I just kept using pucks. We will see.

Will shock level chlorine affect the CYA analysis?

5. ## Re: Tri-chlor pucks to raise CYA

CYA is one of the most inaccurate tests done by pool stores according to experiences on this website. You need a good test kit and the ability to check your own water. Normally those who have used pucks for a bit have really HIGH levels of CYA which leads to problems.

6. ## Re: Tri-chlor pucks to raise CYA

It is so easy to add CYA to a sock or knee-high stocking and hang it at a return. Then you know exactly what is in the pool and you can see when it is dissolved, even if it does not show up on testing.

You can calculate how much CYA you are adding by weighing the tablets and then using the calculator. Better to weigh a weeks worth of tablets to minimize weighing errors.

Your starting CYA could be very high or very low depending on whether a lot of snow and rain is added to the pool over winter.

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