FC won't go above 1 - test results posted

[rdbrya1]

The BBB method was going beautifully for me until 2-3 days ago. We had massive amounts of rain Friday, more Saturday, and all day Sunday as well. I tested the pool water Sunday and my results were:

FC - 1
CC - 0
Ph - 7.7
Alk - 130
CYA - 50

I increased the cholorine Sunday night and tested again last night with pretty much the same results:
FC - 1
CC - 0
Ph - 7.6 - 7.7 (hard to tell)
Alk - 130
CYA - 50

My water is still crystal clear, but like I said there was a lot of rain, so now I am worried there is algae trying to start. Do ya'll typically do some kind of preventivate cholorine when you know a big rain is coming?
So my plan is to add enough regular household bleach to shock the pool (18x32 inground pool, about 20,000 gallons). Since all other levels are fine except FC, should this be the only thing I have to do? Also, is this called Chlorine Lock?

Thanks a bunch for any advice!!

[Watermom]

There is no such thing as 'chlorine lock.'

As far as people having algae issues after rain, it is typically because they don't go out and check their pool during the rain and thus their chlorine level gets too low.

Take a look at the Best Guess Chlorine Chart in my signature below if you haven't already done so. With a CYA of 50, you never want your chlorine to drop below 3. So, even if it is raining, get out there and keep the chlorine levels up!

[rdbrya1]

Thanks watermom! I knew I did not want cholorine to drop below a 3. It had been consistently around 5-6 with no problems until recently. I will admit I did not go out during the rain to test to water :-( I thought that testing it before and after the rain would be okay but now I know! I'm going to get some bleach at lunch today and hope that will get it back up and keep it up. Do I need to bring it to shock levels first and then let the FC slowly drop back down? Or do I just need to add enough bleach to reach a 3-5 FC level? Thank you!!

[Watermom]

If it were my pool, I'd probably go ahead and shock it since it dropped so low for a couple of days just in case there could be something brewing in there.

[rdbrya1]

Great, I'm headed out now to get 7 gallons...I calculated 6.5 96 oz jugs to increase FC to 15 for shock level for my pool. Is it safe or best practice to add all 6.5 bottles of bleach at once or do i need to do this slowly over the next few days?
One last question, does the pump need to stay running 24/7 for the the next few days while I am doing this or is the typical 8 hour (10am-6pm) that I am currently doing fine?

[rdbrya1]

After scouring the forums I hope I answered my own questions but I would love your confirmation to make sure before I mess anything up

1. Yes, it is ok for me to all all 850oz of 6% bleach at one time instead of slowly throughout the day
2. Leave the pump running during the day for my normal 8 hours so it can circulate the bleach
3. Turn the pump off at night and leave off overnight to see if levels did not drop more than 1 ppm overnight

Does that sound like a solid plan? :-)

[Watermom]

What is your volume?

[rdbrya1]

Its a 21,000 gallon pool

[Watermom]

7 jugs (96 oz. each) is 672 oz. or 5.25 gallons. (Not sure where you got the 850.) Adding all 7 jugs at once will be adding 15ppm of chlorine which is what you need. Are you sure they are 6% sodium hypochlorite and not 8.25%?

[rdbrya1]

Oh yes, 672 oz is what I am calculating at 6%. I originally said 850 because on poolcalculator.com I had calculated going up to 20ppm before verifying in the best guess chart that it should actually be 15ppm instead.

I guess I should not have said "gallon" per say, I just meant "jug", meaning the 128oz bottle of concentrated bleach that I have. So based on this I should add 3 3/4 gallons of the 128oz bleach that I have.

I am more unsure on if it is important to leave the pump running 24/7 during this process or if it really matters or not