CYA level/other chemical stuff

sirhicksalot

Member
Feb 27, 2025
9
Pearland, TX
Pool Size
18000
Surface
Plaster
Chlorine
Liquid Chlorine
Hi all,

Recently moved into a new house with a pool, and it's our first pool. Of course they were floating tabs the entire time it was on the market (November-February), and now my CYA is bonkers high, at least 100ppm. I understand that is outside the recommended range. I don't need to SLAM, and I live on the coast of Texas with zero shade to the pool. Is there harm in leaving the CYA high, other than having to maintain a higher FC level? I'm not necessarily in a place to do a partial drain and fill.

FC: 5 (in the process of raising this)
pH: 7.4
TA: 90
CYA: 100
CH: 400
CSI: -.28

Thanks in advance, still trying to wrap my head around all this. I'm using a Taylor test kit.
 
Hi all,

Recently moved into a new house with a pool, and it's our first pool. Of course they were floating tabs the entire time it was on the market (November-February), and now my CYA is bonkers high, at least 100ppm. I understand that is outside the recommended range. I don't need to SLAM, and I live on the coast of Texas with zero shade to the pool. Is there harm in leaving the CYA high, other than having to maintain a higher FC level? I'm not necessarily in a place to do a partial drain and fill.

FC: 5 (in the process of raising this)
pH: 7.4
TA: 90
CYA: 100
CH: 400
CSI: -.28

Thanks in advance, still trying to wrap my head around all this. I'm using a Taylor test kit.
If you maintain the FC following the cya/fc chart it should be fine. But I recommend getting a real CYA value by doing the diluted CYA test to find out if it’s 100ppm or 150ppm, or 300pm as that will dictate how much chlorine you need each day. Your wallet may thank you if you decide to exchange some water. 😉
 
If you maintain the FC following the cya/fc chart it should be fine. But I recommend getting a real CYA value by doing the diluted CYA test to find out if it’s 100ppm or 150ppm, or 300pm as that will dictate how much chlorine you need each day. Your wallet may thank you if you decide to exchange some water. 😉
Ok I'll definitely do that as soon as it stops raining here. I didn't think about the possibility of it being higher.

Is there a way to find out how much water I need to replace to decrease CYA to an appropriate level?
 
Sir,

Why would that be?? Water is almost always cheaper than Liquid Chlorine...

I suggest that you get your CYA down to about 50...

Thanks,

Jim R.
I suppose that's fair. Like I said, still new to all this. Guess I'm going to be looking into draining some water. Do you know of a way for me to figure out how much water to drain?
 
Ok I'll definitely do that as soon as it stops raining here. I didn't think about the possibility of it being higher.

Is there a way to find out how much water I need to replace to decrease CYA to an appropriate level?
It’s a 1:1 ratio. If you need to remove half the cya you’ll need to replace half your water.
 
If you maintain the FC following the cya/fc chart it should be fine. But I recommend getting a real CYA value by doing the diluted CYA test to find out if it’s 100ppm or 150ppm, or 300pm as that will dictate how much chlorine you need each day. Your wallet may thank you if you decide to exchange some water. 😉
Just did the diluted test and I could barely see the dot at 100, putting my actual level closer to 200. I have now purchased a submersible pump and have weekend plans.
 
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