How do I know how much CYA to maintain?

[AmyT]

Please forgive me if this has been covered, but I just can't find the details anywhere. I know that the CYA should be 30-50 and sometimes higher depending on the amount of sunlight, etc. How do I know when my CYA is too low? I feel like I am going through way too much bleach. I am using the BBB method and my CYA is 55. I have to add between 4-12 cups of 8.25% bleach every other night - based on "The Pool Calculator" and my TF-100 test kit. I did the overnight chlorine test and it did drop 1 point, but that's acceptable. Water is beautiful and crystal clear. Is this normal? Based on my testing, the FC drops about 1 point every 12 hours. Is that too much? We are swimming in it about 1-2 hours a day, usually 3 kids. THANKS! Also, what do you do when you go on vacation for 7 days (use pucks or super chlorinate?) - none of my neighbors are competent enough to handle this for me.
FC: 6.5
CC: 0
PH: 7.5
TA: 135
CYA: 55
CH: 280
Temp: 75
Thanks for you advice!

 

[JohnT]

All bathers increase a pool's chlorine consumption, but kids even more so.

A 1ppm drop in 12 hours is low and indicates good water conditions. You are always going to be adding that much chlorine to a pool in a day regardless of the source of the chlorine.

Puck feeders work for vacation if you can deal with the CYA rise, or if you have somebody who can just add your average dose to the pool every night, that will usually get you by, especially if you raise to shock level before you leave.

 

[AmyT]

Thanks for the info. Sounds like everything's pretty normal and working like it should, but I didn't quite get an answer on how to determine how much CYA my pool needs to maintain? Should I shoot for no more shift than 1ppm every 12 hours in my FC? Should I continue to let my CYA go down until the FC drop is bigger than 1ppm every 12 hours? What's the rule of thumb to go by here?

 

[Richard320]

Thanks for the info. Sounds like everything's pretty normal and working like it should, but I didn't quite get an answer on how to determine how much CYA my pool needs to maintain? Should I shoot for no more shift than 1ppm every 12 hours in my FC? Should I continue to let my CYA go down until the FC drop is bigger than 1ppm every 12 hours? What's the rule of thumb to go by here?

http://www.troublefreepool.com/pool-school/recommended_levels

Also check pool-school/chlorine_cya_chart_shock

With your CYA at 55, minimum FC is 4.5, target is higher, and the color-matching test block maxes out at 5. Which puts you in the position of having to use the FAS-DPD test every time. To me, anything between 4 and 7 looks like 5. So much for the quick daily check.

Realistically, most people lose about 2 ppm FC per day. If it's really hot and sunny, and you have a couple of kids in the pool, 3 ppm would be pretty normal. A large pool party - all bets are off. 12 people can turn a sparkling pristine pool into a cloudy mess in no time.

You're just going to have to learn your pool's personality.

 

[AmyT]

Yes, you are right. I have to use the FAS-DPD test every time - meaning every day. I am going to keep working on getting my CYA level down and hopefully I'll be able to switch to the Taylor test and use the test blocks.

Thanks for your advice on the CYA. Any suggestions on preparing for 12 little girls as we are having a swim party next weekend? Should I up the FC about 2 ppm above target and make sure my Ph is 7.5 - or just treat it after they leave?

Thanks for your help!

 

[Richard320]

Dump about 2 ppm extra bleach in just before it starts. If there's a meal break, dump in 2 more. When it's over, dump in 2 more. Expect it to look cloudy. Test it the next day and treat it normally.

For more exciting first-hand tales, read some of these threads. I vaguely remember someone figuring out the FC loss per swimmer hour.

 

[AmyT]

Awesome! It sounds like great advice just a little more aggressive than I would have thought. Yes, there will be a pizza break and I'll utilize that time to add more bleach. I don't know what I'd do without The Pool Calculator. People who don't know about it are doing a lot of guessing. THANKS AGAIN!