View Full Version : CYA, hot water, and South Florida

05-05-2006, 06:47 PM
Hello everyone. I have a question about CYA levels. Should temperature zone, sunlight exposure, and water temperature affect how high a level of CYA I should keep in my pool?

Where I live here in South Florida, the most common recommendation for CYA is 60ppm, which itself seems to require an FC level of 5 - 10 using the "best guess CYA chart". What is everyone's opinion on using a 60-90ppm of CYA vs. 30-50ppm (with a FC level of 3-6)? My thinking is that perhaps with a 60ppm CYA and FC level of 5-10, I would get maybe an extra day or 2 of 'float' (since there is a 5ppm variance) before I need to add bleach again. I'm only available to test and bleach 2x during the week.

In the summer, my pool gets full day exposure to the sun, and the water temperature often gets in the 90's.

Hope this post isn't too rambling, but I would appreciate any comments on the subject.



05-05-2006, 07:18 PM
If you are only available 2x a week to test and dose it with bleach, it might make sense for you to run high cya / high cl. There are some people on this forum who intentionally do this. I think one of my fellow moderators, Janet (aylad) does. I'll ask her to take a look at your situation and share with you what she does. (I think I'm right that she runs cya - but not 100% sure.)

05-05-2006, 10:21 PM
I live in south florida, hollywood. i run a low cya 30-40ppm but i test my water all week, usually 4-7 times a week. the water does get tons of sunlight and get very warm during the summer but i only add bleach twice a week. i do add high levels of bleach though when i add. usually i add 2.5gallons/week of 10% bleach. i think whatever works best for you personally is the way to go as long as you are on top of it. i hope that helps somewhat?


05-07-2006, 09:35 PM
I live in northern Louisiana, where my water temp is currently in the low 80s, and will be in the high 90s before summer is over. My pool is in full sunlight all day, so I intentionally run CYA levels of 80-90 with FC levels at 7-8 ppm. For me, that means I keep a trichlor feeder running at the lowest setting, and dose with bleach twice per week, shocking after a big swim load (using bleach). After testing daily for a week or two, you'll get a feel for how often/how much bleach you need to add, but this has worked very successfully for me for 5 years now--and my pool is open year-round.


05-08-2006, 08:45 AM
Thank you for the replies. It sounds like I'll hopefully not have issues running with a bit higher CYA.

In an effort to keep my first post short, I put the 'meat' of my question in there. Now I'll add a little more to the story. I built my in ground, exposed aggregate pool in the summer of 2003. I went to Pinch a Penny (local pool store, I believer it's a chain) for testing and supplies afterward. My pool builder, as part of the warranty, wanted at least monthly chemical tests by a pool store to verify I was properly balancing the pool, and Pinchapenny had anice computer that could pull the reports when needed and I wouldn't have to keep papaer lying around. Anyway, very soon after the pool opened, I found this website, bought a kit, and took care of my own pool with my new knowledge (I balanced the pool and got the "professional" test, just so my numbers would look good).

My pool was beautiful, all the time. Then we got hit by Frances and Jeanne, I lost power to the pool for 2 weeks. I cleaned it the best I could, I even added bleach and acid as needed and agitated the pool by hand. Unfortunately, by that winter, I was getting yellow algae with all my pool stats in the 'normal' places. All winter I fought it. I even spent a full month with the bleach levels at shock levels, diligently adding bleach every day (not much loss in the winter), brushing, and cleaning the filter. The algae still crept in again once I tried to let the bleach levels return to normal. We had hurricane redux with Wilma and again I spent last winter trying to free the pool of algae.

Basically, if I don't keep higher levels of FC (8+ with CYA around 40-60), the algae starts showing up again in small spots. Unfortunately, I have Wednesday and the weekend to to take care of the pool, and I sometimes dip down in that period, and get a small outbreak. I'm going to try to raise the CYA a bit and see if I can hold on to the bleach level while still being effective at preventing the algae. I'm also going to start adding to polyquat weekly to see if that can help. I know I'm messing up the 'science' of my experiment by changin 2 variables, but I'll spend some extra $ on algaecide if it 'may' help prevent the extra trips for bleach and extra time for cleaning.

If you've read this far into the post, thanks for hanging in there. I hope I make some sense, but this is like therapy. I NEEDED TO VENT!!

If anyone had similar experiences after the hurricanes (most of the respondents seem to be from 'hurricane' areas), and have been able to control this, please let me know!

Thanks for reading,


05-08-2006, 09:10 AM
Hi, Mike,

Based on my very limited understanding of agaecide, your pool sounds like the perfect candidate. We'll all be interested in your results. :)

05-29-2006, 12:05 PM
I'll update here for anyone who's interested. I'll indicate what I am doing and some general results. This is by no means scientific since I have changed quite a few things at once, but my pool is looking good, so why should I care (much)?

My previous problem was yellow algae showing up very quickly when the FC dropped anywhere below 5ppm, with a CYA of about 50. I work away from home much of the week so I can only maintain on Wednesdays and the weekend.

Since I started this thread, I have added an initial dose (10 oz.) of 60% polyquat to the pool, and added 4 oz. per week on Sundays ever since. Also, since I was interested in adding CYA to raise the levels a little higher, to try to maintain my FC a little longer, I started using trichlor in a feeder (2 3" pucks in Rainbow at 1.5 setting, whatever that means). I figured this would give me a slow increase in CYA while having the added benefit of adding chlorine. This has given me a FC reading of around 4, consistently. I haven't retested the CYA, but I am only on the second 2 pucks, so it shouldn't be significantly higher.

In conclusion, I haven't had any algae, I've been using small amounts of tri-chlor, and I've been using 4 oz. maintenance doses of polyquat. So far, so good. At some point I will need to stop the trichlor once CYA hits 60 - 80 range, then I will be able to see if the FC levels from 10% bleach holds until I can add more.

Hope this 'real world' experience can be useful to someone.


PS - Can't wait to get my upgrade 234 kit! My r-0010 drops are running low!

05-29-2006, 12:15 PM
Congratulations on handling your situation--sounds like it's working for you. Here's hoping this season leaves us alone!!