The Perfect Storm

[janmo]

Please tell me what to do.

My pool water was perfect using the BBB method. I went on vacation. Severe storms came through, knocked out the pool pump, lots of tree stuff (along with a plant, a bull frog and an umbrella) blew into the pool. Neighbor watching pool had a heart attack so I had no idea this was going on. Pool sat for three days.

I have an inground 20,000 gallon vinyl. It is green and cloudy and there is a yellowish film on the bottom of the pool that brushes off easily.

Right now I am reading:

FC 0
CC 0
PH 7.8
ALK 180
CA 40

Thanks for any suggestions!!
Janis

[KurtV]

Janis,
Hope your neighbor is OK.

1. Bring your water to shock level. Per the Best Guess Table (http://www.poolforum.com/pf2/showthread.php?t=365), for your CYA level of 40 (assuming you meant CYA where you typed CA), that's 15 ppm which will take about 2.5 gallons of 6% bleach in your 20,000 gallons of water.

2. Test the water frequently (3x per day, preferably) and add enough bleach after each test to bring the free chlorine level back to 15 ppm.

3. Keep this up until the water is crystal clear and it holds its free chlorine level overnight.

4. It may take several days. During this time run your filter pump 24x7 and vacuum debris and dead algae to waste if you can do that with your filter. Backwash (or clean if you have a cartridge filter) as needed.

Good luck.

[janmo]

After I posted that I remembered that I forgot to post that the neighbor is recovering quickly and there wasn't much damage. It has taken me a couple days to even get to the pool because of the concern there, but she is now home and the prognosis is good.

Thanks, and I am on my way to pick up more bleach.

Do I need to do anything about the ALK or PH?

And yes, I did leave out the Y on CYA : )

Janis

[KurtV]

Sorry, I meant to mention the pH. Keep it in the lower end of the 7.2-7.8 range (like 7.2-7.4). That will make your chlorine more effective. Test for and adjust the pH before you shock; you won't be able to test pH accurately while you're at shock levels of chlorine.

Don't worry about the Alkalinity for now. You probably won't ever need to worry about it unless you you can't keep your pH down without frequent acid additions or if you get scaling or clouding (which will probably only happen if your calcium hardness is also high). Again, though, don't worry about it at all for now.

[janmo]

Kurt, thank you so much for all your help!

I added some acid to lower the PH, and will start shocking later today.

Janis