Why can't I keep FC in normal range?

[mekaw]

Hi all. New pool owner doing pretty well with BBB method. My only concern is my FC. I add chlorine every evening. I test it in the morning before work and it's perfect. I get home 10 hours later and my FC is like 1. Here's all my test results:

This morning:
FC 4
TA 90
Ph 7.6
CYA 40
CH - didn't test

I need to tell you guys that I live in VA and it is very hot. My pool sits in the sun from sunrise to roughly 6pm. My cya seems ok, or I thought so. So how do I keep chlorine in the pool?
Also, I run my pump all day and for 3 hours after I add chemicals. I turn it off at night. Is this wrong?

Please help.

Thanks.

 

[257WbyMag]

What is your CC?

So, your FC is exactly the same in the morning as it was when you went to bed the night before?

If you are one that gets lots of direct sun on the water, you may need to up your CYA a bit. I would like to be sure that you aren't losing FC to organics in the water first.

 

[diverman57]

so you are using about 3 ppm per day of chlorine, a little high but thats about what my pool
uses as it is in the sun all day. so if you are consistently losing 3 ppm per day, you need to start
the day a little higher. i raise mine to about 6 ppm every evening and that way i never go below
3 ppm the next day. getting down to 1 ppm with 40 cya is asking for trouble.

 

[Butterfly]

You should do an overnight FC loss test to rule out organics.

If you pass the test, then you should consider raising your CYA to about 50.

 

[woodyp]

I bump my target FC to 2ppm over what the chart says for a cushion. I lose 3-4ppm per day, all day sun. Taking CYA to 60 or so myself. and 70 if that doesn't work!

 

[beezar]

I (un)fortunately have a separate spa and pool so I have to maintain 2 bodies of water. On the pool, was losing 2-3ppm, and the spa, 3-4ppm per day; CYA was 70 on both, FC overnight loss test 0, LOTS of sun on both each day (more so on the spa).

So, no, not out of the question for FC to do that in sunny hot climates; important to do the FC overnight test to make sure there are no organics causing the FC drop first, and if that's ok, bump up CYA like others have mentioned.

But the thing that really helped me was to get a salt water generator for the pool (best thing I did; well, that and borates). And I put a solar cover on the spa which cut the loss of FC from 3-4 per day to 1.5-2 per day, and life got much easier (couldn't put a SWG on the spa due to flagstone waterfall).

Only have had the SWG a few weeks, but life is SO much better not worrying about lugging chlorine and adding it and worrying about FC drop. Now the only thing I need now is the Margaritaville frozen concoction maker that woodyp has...