Chlorine Consumption - New Pool


May 27, 2020
I have a new pool that has been filled for 3 weeks and I am just wanting to make sure I am maintaining FC the way I should. My 13,500 gallon pool gets direct sun for the majority of the day. It's only shaded by the house (on east side of pool) until about 9:00 then it's full sun. My CYA level is in the 30-40 range and every evening I've been adding anywhere from 2-3 quarts of liquid chlorine to get a FC level of 5. The FC level wiIl stay at 5 FC overnight but by around 7:00 or 8:00 PM I'm down to 1 or 2. I added 1 lb. of dry CYA in a sock in a skimmer yesterday to try to bring the CYA by 10 hoping that will help reduce chlorine usage. My concern is that at some point in the day my FC is dropping down below the minimum recommended FC level, probably sometime in the afternoon. During the week the pool is being used in the late afternoon and early evening most likely when the FC level is below the minimum recommended level on the FC/CYA ration chart. Is that concerning or is it not a big deal as long as I add enough chlorine in the evening to bring the FC level back up? I may be overthinking this but I got a new toy and just want to make sure I'm taking care of it.


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Silver Supporter
Jul 8, 2013
Columbus, Ohio
Try to stay on the high side of the suggested range so as your FC level drops during the day it stays above the minimum. People in your climate usually hold a higher level of CYA due to the sun. I'd probably plan on 50 until you hear from someone else that's in TX. A SWG seems very popular in your climate.

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
I agree that this time of year a CYA of 30-40 wasn't nearly high enough. Our TX sun is just too intense, so your FC was susceptible to the sun and probably dropping a bit too fast for that reason. The other concern is adding 2-3 quarts in your 13.5K pool is equivalent to about 4-5 ppm of FC. That's a bit more than we like to see used-up each day, however you are using the pool consistently. Still, you might want to do an Overnight Chlorine Loss Test to be safe. We still have about another 60 days or so of intense sunshine ahead of us, so it would be good to rule-out algae before you increase the CYA too much higher.


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

You should not be trying to keep your FC between the minimum and your target of 5.. You should be trying to keep your FC at 5 ppm or above.. Sometimes things happen and the FC will drop a little below 5, but you never want to get even close to the minimum..

Being in Texas, I would try running a CYA of about 50...


Jim R.
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