When does "No problem" become a problem?

[flipflop]

For the past 12 years, we've gone with the pool store's recommendations and used nothing but pucks or sticks and powdered (cal-hypo) shock. We were told when our pool was first opened that we needed to shock once a week, and we stuck with that pretty religiously. But now that we've adopted the BBB method and are following the recommendations here at TFP, we've not had to shock the pool. Not even once. Granted, we've only been on this method for about 10 days, but I was sure that after a couple parties with a relatively heavy bather load it would surely be necessary. But so far the CC remains at 0.5 or less (can't really measure below that, anyway), overnight FC loss is 1ppm or less, and the water's crystal clear. I take a reading in the morning and dump the appropriate amount of bleach in, and that's it. FC does decline steadily over the course of the day as one would expect, but never drops below 1.5. pH is stable at around 7.6, TA holds steady at 100, and all is well with the world.

Should I just not worry about it?

 

[imwarren]

Sounds like you are starting to understand the bbb method

1 question though what is your cya? At the recommended levels 40-50 the lowest your fc should ever get is 3. Your post states your fc drops to 1.5 which might get you a problem unless you are running a lower cya

 

[flipflop]

CYA is exactly what got me started on BBB. We had CYA readings around 100 and when the pool store guy wasn't able to explain to me adequately what that meant, I came here to read up on it. Needless to say, I was a bit unhappy that nobody over the past 12 years had explained that to us. So, after some aggressive water replacement we got our CYA down now to around 60.

I know 1.5 is on the low side, but the alternative is testing and adding bleach several times a day. Or springing for a SWG.

 

[Butterfly]

With a CYA of 60, the FC should be between 5 and 9, and never below 5. You are setting yourself up for problems if you allow the FC to drop below 5.

You should be able to add bleach/liquid chlorine each evening to reach about 9 or 10ppm FC(preferable after the sun is off the pool). The next evening when you test again, it should still be at 5 or above. Then, raise FC back up to 9 or 10. Once daily manual chlorine addition should be enough for maintenance on any pool.

If you are having to add chlorine often during the day to maintain correct FC, then something is wrong. How much FC are you adding?

 

[flipflop]

I'm generally not adding more than is needed to bring it back up to around 5ppm. So I suppose I'm starting at minimum and then falling off from there. The pool is in full sun from sunrise to sunset, so losing 4-5ppm of FC over the course of the day doesn't surprise (or worry) me. I guess I just need to start the day with a much higher FC level.

 

[frogabog]

Yes, make sure to start the day (or end the day actually, I prefer to dose after dark when everyone is done swimming) at your maximum target level for your CYA level.

Assuming all is well, and you don't lose more than 1ppm overnight (really should lose closer to none when all is well) your pool should only lose ~50% (or less) of your chlorine throughout the day. It is very important not to fall below minimum for your CYA level, so whatever you have to do to make sure that doesn't happen (even dosing to 10ppm at night instead of 9ppm) will be good for your pool. Bear in mind that if your bather load is high, you'll lose more than normal. You can combat that by adding a ppm or two more when the load is expected to be higher than normal.

 

[flipflop]

Thanks for the advice. I'm going to start that routine this evening.