Cya Is Around 90+, Need To Reduce

[OttawaGreg]

I'm into the 4th month of Dychlor/Bleach method and found my CYA has risen from it's starting point of 60. Other then one trouble from neglect the water has been very stage for the past few months.

Current reading tonight show things are up a bit;

pH=7.8, TA=100, CYA=90-100.

My usual readings were pH=7.5, TA=80.

The Taylor test kit just says to lower CYA to use a non-stabilized chlorine for a while. lithium hypochlorite is the only chlorine I have not listed as stabilized, so I assume it's not stable then?

Should I then stop using bleach entirely and switch to lithium hypochlorite or just top up with lithium hypochlorite but continue to use bleach? I've been using MPS as a top up once a week until now.

thanks in advance for any ideas. BTW, the water is fine, I have no foaming issues and it looks and smells great, so I'm not sure I have a real problem here and am just checking. I guess another thing I could to is bring a sample in and get TDS tested.

thanks,

Greg

[hrustar]

The only real way to lower CYA is to dump and refill. The sun will destroy some CYA, but not effectively of fast neough to make a difference. The best thing to do is to stop using Dichlor and switch over to bleach (see Nitro's Dichlor/Bleach method). Like you, my CYA was off the charts high (higher than you). I switched to bleach and have no problems. The high CYA has not affected the bleach's ability to do its job, or required the use of lots of bleach. For example, i use about 3 to 5 ounces of bleach a day.

SO don;t sweat the high CYA, and next time when you refill, watch the level until it reaches 30 or so, then switch to bleach

[chem geek]

FYI: bleach and lithium hypochlorite are both unstabilized (i.e. neither adds to CYA) and neither increases CH either. However, lithium hypochlorite is 5-6 times as expensive as bleach for the equivalent amount of added FC.

[OttawaGreg]

FYI: bleach and lithium hypochlorite are both unstabilized (i.e. neither adds to CYA) and neither increases CH either. However, lithium hypochlorite is 5-6 times as expensive as bleach for the equivalent amount of added FC.

Thanks all, BTW I am using the bleach method, have been for months. Somehow my CA has risen and I'd like to being it down. I guess then I will keep using bleach and topping up the water with fresh and over time it will drop on it's own?

I had to dump a bunch of chlorine in a few weeks ago when the water went south. I guess that is what caused it.

Greg

[chem geek]

The only way that the Cyanuric Acid (CYA) level would have risen is by adding stabilized chlorine (either Dichlor or Trichlor) or CYA itself (cyanuric acid powder or Instant Pool Water Conditioner).

Did you add Dichlor a few weeks ago -- is that what you meant? Also, why did the water go south, from an unusually high bather load without enough chlorine added or something like that?

[OttawaGreg]

The only way that the Cyanuric Acid (CYA) level would have risen is by adding stabilized chlorine (either Dichlor or Trichlor) or CYA itself (cyanuric acid powder or Instant Pool Water Conditioner).

Did you add Dichlor a few weeks ago -- is that what you meant? Also, why did the water go south, from an unusually high bather load without enough chlorine added or something like that?

The water went south because I forgot to top up the bleach after the last use and it was low, then I was away for a few days unexpectedly so it got no maintenance. When I got back it was light brown tinge and bad odor. I shocked it well with Dychlor and MPS, then lots of bleach later. It came back very well and looks fine. I just hadn't taken a full drop test reading in a while so I did them all and found TA higher then usual and pH as well. Now I see CYA up near 100 and wonder if the water will stay OK or am I going to need to dump this eventually.

My hope is to lower the CYA and maintain the water as I was doing with Bleach & MPS. It was going so well!

Greg

[bart6453]

The only way that the Cyanuric Acid (CYA) level would have risen is by adding stabilized chlorine (either Dichlor or Trichlor) or CYA itself (cyanuric acid powder or Instant Pool Water Conditioner).

Did you add Dichlor a few weeks ago -- is that what you meant? Also, why did the water go south, from an unusually high bather load without enough chlorine added or something like that?

The water went south because I forgot to top up the bleach after the last use and it was low, then I was away for a few days unexpectedly so it got no maintenance. When I got back it was light brown tinge and bad odor. I shocked it well with Dychlor and MPS, then lots of bleach later. It came back very well and looks fine. I just hadn't taken a full drop test reading in a while so I did them all and found TA higher then usual and pH as well. Now I see CYA up near 100 and wonder if the water will stay OK or am I going to need to dump this eventually.

My hope is to lower the CYA and maintain the water as I was doing with Bleach & MPS. It was going so well!

Greg

Use the pool calculator to figure out how much water to remove and then replace. (If you have an ipod, get the pool calculator app, tis a thing of beauty!)

Next time you shock with chlorine, use bleach as not to add additional CYA.

[chem geek]

If the CYA go up to around 50 ppm or so, then I wouldn't worry about it, but getting to 100 ppm starts to get into the range where some people reported more problems. So the advice of partial drain/refill to lower the CYA is good. It might be that you'd be OK at the CYA of 100, but the risk is higher due to the roughly 3x slower oxidation and disinfection rates unless you were to maintain a much higher FC level closer to 13 ppm instead of 4 ppm. Since one normally gets the FC lower before a soak, say 1-2 ppm, then that would require 3.3-6.7 ppm before a soak to be equivalent and though outgassing of chlorine would be similar, there would be more monochloramine produced (from your sweat and urine) and that might be objectionable during the soak.