0% Chlorine all summer

[ja123]

So last year I became a new pool owner and before I found this site, I added about 6 bags of cal hypo to my pool to shock it and ran the filter for a few days non-stop. The cal-hypo of course raised my CH but kept it within safe range.

Once I found this site, I tried to apply the slam process (also using a TFP test kit) with 6% bleach but could never get the chlorine levels at the recommended amount (my CYA was about 30-40). I gave up after about 20 bottles of bleach I don't know if there was something in the water I just couldn't get rid of or what, but I didn't have the funds to keep buying massive amounts of pool chemicals. So instead I was able to keep the water still sparkling blue by just adding ONE bottle of bleach a day or every other day sometimes. I added one bottle in the morning and by the time I was home in the evening my chlorine level was 0 or very low

Any recommendations on how to get the pool to hold the chlorine this season?

 

[dallasaggie]

My initial thoughts:

Where are you buying your bleach? Does it have an expiration/best by date?

How are you testing your chlorine levels?

 

[ja123]

I was testing them originally with recommended TFP test kit/Taylor Test kit. The bleach was being delivered by Walmart not sure what the dates were

 

[splashpad]

I would suggest a lower CYA level (20-30).
Make sure to test & balance all parameters using FC/CYA Levels and PoolMath

 

[Richard320]

All theoretical without test results, but here's some ideas:
Over the winter your CYA broke down into ammonia. It takes ten times the chlorine to neutralize ammonia, so it will use a whole lot and not register. That matches. The chlorine will disappear almost as fast as you pour it in. That also matches. Eventually chlorine and sunlight eliminate the ammonia. However you still have zero CYA to protect your chlorine from the sun, so any bleach you add disappears within an hour or two -- longer if done after dark -- but that's enough time to kill any algae spores to keep the water clear. Note that clear and sanitary are two different things. But anyway, the water remaining clear matches your scenario as well.

Start with test results. Results we can trust, not pool store testing, not test strips. See what your CYA result is. Test the Combined Chlorine. Maybe run Overnight Chlorine Loss Test. We'll get you straightened out.

 

[ja123]

It is very possible that the bleach may have been old wish I knew to check the dates when I purchased them. This year will try a stronger bleach 12.5 and see what happens, should be opening the pool next weekend will post results.

 

[Razorhog]

The "Born on" date is just as or more important than the % concentration. I recently bought some 10% from walmart that was born in December of 2018. It must have been stored correctly because it is hitting exactly what I expect the FC to be.

 

[MrBfromNC]

It is very possible that the bleach may have been old wish I knew to check the dates when I purchased them. This year will try a stronger bleach 12.5 and see what happens, should be opening the pool next weekend will post results.

I now get my 12.5% chlorine from a pressure washer supply company in North Raleigh. He said they get a new shipment every other week. I can tell because when I add my LC, it works out to more like 13-14%. Booyah!!

 

[Donldson]

So instead I was able to keep the water still sparkling blue by just adding ONE bottle of bleach a day or every other day sometimes.

It might seem counter-intuitive, but you used way more bleach that way than if you had kept with it from the start. Since your FC was always dropping to zero whatever was in the pool had plenty of time to regrow every day. You would dose in the morning, kill a bunch of it, but by the next day it had grown right back. Had you stuck with it in the beginning your water would have held chlorine far better. A typical TFP pool loses 2-3 ppm of chlorine a day, which for a pool your size would mean an average of 1-2 cups of 6% chlorine. That would have been a gallon every week or two, not every day or two.

Using 12% means you will lug fewer bottles, but it doesn't change the core issue: you need to stick with the SLAM. If your FC is dropping to zero then your water is infested with something, clear or not. It might feel like a lot of chlorine and a lot of money, but if you see it to 100% completion and stick with your regimen from there (not allowing FC to drop below the minimum for your CYA level) then you will never have to do it again. That's when the savings kicks in big time.