CYA Went Up! How???

[hellstorm2004]

Hello Everyone,

About 1.5-2 months ago, I dropped my CYA to 70 from about 110. There were heavy rains for three days straight over here, and I tested my water yesterday, expecting to see a lower CYA, but no, my CYA is now 100. I am a little lost about how the CYA went up. Bad testing? The weather was cloudy, so did not test it in sunlight. But i dont think that is the case. My pool hasn't seen a chlorine tab in 4 months now. I only use bleach.

 

[domct203]

Hello Everyone,

About 1.5-2 months ago, I dropped my CYA to 70 from about 110. There were heavy rains for three days straight over here, and I tested my water yesterday, expecting to see a lower CYA, but no, my CYA is now 100. I am a little lost about how the CYA went up. Bad testing? The weather was cloudy, so did not test it in sunlight. But i dont think that is the case. My pool hasn't seen a chlorine tab in 4 months now. I only use bleach.

If you have not used any form of stabilized chlorine (trichlor tablets, dichlor granular, etc) the only other cause would be inconsistent testing.

If it was cloudy out that could make the dot seem to disappear sooner, giving a false higher reading.

Dom

 

[hellstorm2004]

OK. Will do a repeat test when the sun shows its face. Thanks!

 

[chem geek]

If you tested after the rains you had but did not wait for the water to circulate, then you'd measure an artificially lower (diluted) CYA reading before the rain water completely mixed with the pool water below it.

 

[hellstorm2004]

Yup. Tested it today. CYA is 60 now!! With so much rain, i thought it would drop a a little more! Bad performance by Zeus!! :farao:

But at least its a drop.

I had one more question, dont want to start a fresh thread for it, I am going on a long vacation, 4 weeks to be exact, should i just raise my FC to shock levels before i go? My FC loss is about 3ppm a week, I think it should reach normal levels by the time i get back. I dont want to go through another SLAM!

 

[Texas Splash]

Taking your FC up to SLAM/Shock level just prior to leaving is a good idea. Sounds like your water temp is dropping to only go through 3 ppm per week. Still, I'm not so sure that will hold you over for 4 weeks though. If you don't have someone available who can add a little bleach to your pool every few days, you may have to use a floater or in-line chlorinator with a tab or two while you're gone. Remember you can always plug-in your numbers on the Poolmath calculator (link below). At the very bottom of the calculator you can experiment to see what the effects will be of adding 1 or 2 8-oz pucks to your water (i.e. FC and CYA). You've done great to get that CYA down, but based on your time away and average FC loss per day you may have no choice but to use a tab or two to maintain some consistent sanitation. If you do, it's not the worse thing to happen and won't kill your CYA level with just 1 or 2 tabs. You'll still be in a good manageable range (i.e. 70-ish).

 

[graler]

When i leave the pool for an extended period of time I throw some tabs in a floater. The CYA gain isn't going to be enough to impact anything.

 

[hellstorm2004]

My main concern are the leaves that keep dropping. Will fall going on, my pool gets loaded with leaves and all sort of debris. Living next to a park definitely does not help!

I would look at floaters and see what i can find. So would you say FC at shock levels and a floater or FC at normal levels and a floater?

 

[hellstorm2004]

I am also thinking of raising my borate levels to something around 35-40. That should be a little bit helpful. I do have an inline chlorinator. I might have to use that in medium settings.

 

[Texas Splash]

I would bump FC up to SLAM level just before you leave, and also put a floater in the water OR use your in-line chlorinator. Either should be fine with a couple tablets.

 

[hellstorm2004]

Ok! Thanks!

 

[gary300]

How much acid do you use per month? PH rising too high would also be a consideration.