Free chlorine is non existent

Thanks. Adding CYA may help?

Yes, if you're losing your chlorine to the sun. CYA and stabilizer are the same thing. Also called "balancer", "conditioner", look at the ingredient label. If the main ingredient is cyanuric or isocyanuric acid, it's the right stuff.

However, if you're losing your chlorine to stuff in your water, the stabilizer isn't going to help you much.

Janet

Houston, we have a problem. I am losing chlorine overnight. Please advise on next steps.

I presume the following. Drain the pool as much as possible. Open up the filter and throughly clean the grids.

Refill and chlorinate/stabilize

Experts please help.

I have owned this pool for 10 years. The first 8 years were a breeze. The last 2 have been difficult. The issue this year has never happened before.

Thanks!

I would start by putting in 7 gallons of 6% bleach tonight--that should push your FC to around 15ppm.
In the morning be prepared to add up to 7 gallons more and keep FC up until it doesn't drop so drastically overnight.

Carl

OK will do.

Local pool shop suggested I check for phosphorous. They checked a sample. It registered at 1000 ppb. They gave me a chemical that reduces the phosphorous. I will try that. Anyone have any experience with this?

Yes, we are familiar with it.
No, you shouldn't use it -- it won't do ANYTHING to solve your current problem.

The fact that several days ago your chlorine went to 1 ppm in just an hour after a large dose tells me you have a VERY high chlorine demand, most likely from ammonia. Please read this page:
spring-swimming-pool-startup-problems.html

It's possible to have NO stabilizer (so you lose chlorine during the day) AND ammonia (so you lose chlorine day AND night).

Draining 100% and refilling is an option.
Draining 50% will remove 50% of the ammonia

If you don't remove it all, you'll have to add bleach till you destroy all the ammonia gone. Since I don't know how much ammonia you have, I don't know how much more bleach it will take.

But, if you aren't going to drain, do like Carl says, and add larger doses at night. Once you see high chlorine in the morning, you are close to being done.

Ben

Carl/Ben: Thanks. I will stay the course with massive doses of bleach night and day until I can get the FC up. I also bumped up the ph a bit as recommended in the link.

Oh man, these pool stores...all they want to do is...well...sell us chemicals and make money. : (

I really do not want to drain and refill.

Happy to report that, for the first time this season, my pool is holding a FC level in the morning.

Ph is 7.6
Chl is 3.0

Friday night I added bleach. Sat morning the FC was still weak. Sat I added borax to bump up the ph followed by more bleach. Sat night I added more beach and finally Sunday morning things are good. I have also been running the pump 24/7 since Friday.

Now on to the phosphorous. Should I attack this as a separate issue or are you saying I can ignore this? Thanks much.

Glad to here of the progress. I'd go ahead and smack it hard with bleach one more day. If you again maintain FC over night without losing more than 1ppm, then you should be ok. Don't worry about the phosphorous. It is usually just another way for pool stores to drain their customers wallets selling them phophate removers.

All is good here. I hit the pool with another dose of bleach last night. The pool continues to hold a good free chlorine level in the morning. Thanks for all the help. I am glad I found this web site!