CYA Levels

[sugast]

My pool is 1 year old. I'm using an in-line chlorinator with 3 inch tabs. I've been studying the TFP method and have learned the tabs add CYA over time. My questions is how can the CYA only be 60 after using the tabs religiously for a year? Shouldn't it be higher? I live in Dallas and the pool is in direct sunlight all day. I've never drained and refilled but the evaporation causes me to add water often. My guess is that's serves as an ongoing drain and refill. Is my logic correct?

Before you guys scold me about using the tabs over chlorine, here's why. I travel a lot and can't add the liquid chlorine daily. Also, is there a CYA/FC chart based on using tabs versus liquid? I'm following the rest of the TFP method!

 

[jblizzle]

Evaporation and refill will not lower the CYA. Do you get enough rain to offset the CYA rise? Hot water and a lot of sun can lead to some degradation of the CYA in the pool. Perhaps up around 10ppm per month.

There is no separate chart. The FC / CYA relationship is valid regardless of the source of chlorine.

 

[mknauss]

How are you testing your pool water chemistry?

 

[sugast]

currently I'm using a Pentair 78HR at home and Leslies uses a Taylor test. My home test doesn't measure CYA so I've relied on Leslies. Yesterday, I ordered the TFT 100 with the swirl device.

 

[sugast]

We did get a fair amount of rain in the spring but not as much lately. I do have to add water 2-3 times a week though.

 

[mknauss]

Let’s see what you get for CYA with the TF100.

 

[sugast]

I know...I'm anxious to see the difference! Quick question on the CYA/FC chart: It says that my target FC is 7-9 since my CYA is 60. Currently, I'm at 4. Should I use liquid chlorine to boost it that high? I'm not sure my in-line will get it that high because I already have it on a flow setting of 4 and the highest flow is 5.

Also, the chart shows my slam level FC should be 24. How long does it have to be at that level and how do you know when it's time to slam? Thanks!

 

[mknauss]

You should use liquid chlorine exclusively, but that is up to you.

If your water is cloudy, you are losing too much FC each day, or you have visible algae, time to follow the SLAM Process

You can also do an Overnight Chlorine Loss Test

 

[jblizzle]

Yes use liquid chlorine to get the FC up asap. You should really stop using the tablets if your CYA is really that high.

You only need the SLAM process of you see algae, or your water turns cloudy, or you get significant CC showing up.

 

[sugast]

got it...thanks If I use the liquid, don't I have to add daily? I'm not around daily?

 

[mknauss]

If you are not home every day, like me, get a SWCG. Best investment you will ever make.

 

[sugast]

thanks!