CYA drop after rain

[jojoman]

OK, after 4 inches of rain in a week my CYA fell to 50 on a SWG pool. It was a little low before the rain but now it's even lower. I do not have any CYA on hand but i do have a few tri-clor pucks left over from when we had an above ground pool. Think it's okay to use them, i have been adding clorine already as the water has been to cold( that will change soon) for the SWG to opetate?

Bonus question: Where is the water going during the rain. All i can think of is out the skimmer caps because there aren't any drain lines install. Then i thought the caps would float off, but maybe i'm wrong on that. I watched during a down pour to see if the pool would overflow but it fills until the bottom of the bullnose on the coping then stops. Then in two or three days it drops back to it's normal 1 1/2 inches below the bullnose of the coping.

 

[jblizzle]

Sure you can use them. Check PoolMath to see how much CYA each ~8oz puck will add and make sure you keep track how many you use.

Likely the water is leaking out at the bottom of the bull-nose and that is why it does not go higher. Could then drop due to evaporation, but 1.5" in LA in a few days seems little high to attribute to evap.

 

[jojoman]

Ok, thanks. I have just see so much as to why not use the pucks i thought that in this case i could use them as i need more CYA and chorine without much harm. Looking to use up those few pucks leftover and save a few bucks also.

With an average annual rainfall of 64 inches around here we could almost fill the pool with rain water in a years time.

 

[JayBauman]

With that amount of annual rainfall, it won't hurt to use the occasional puck. But I'd guess it would take quite a few of them to make a substantial CYA contribution during the rainy season!