Starting over after power outage-- No Chlorine or CYA

[chem geek]

It can happen very quickly. I had this happen to me during one spring opening a few years ago and it took less than one week -- probably 3-4 days. My CYA went from around 30 ppm to close to zero, the pool turned cloudy, and I had a huge chlorine demand from ammonia and partial CYA products (probably biurate and allophanate) that came from bacterial biodegradation of CYA. A log of my chlorine usage to clear the pool is in this post. A technical explanation of the biodegradation of CYA is in this post.

Note that I had to add a LOT of chlorine and that it got consumed very quickly early on, so add it multiple times during the day measuring until the chlorine starts to hold. Once you get an FC reading that is mostly stable (i.e. not dropping to zero in hours), then you'll know that you've killed off the bacteria because they can't survive when FC is present. It's at that point that you can start to add some CYA to the water, but not too much (say, not more than 30 ppm) until you lose < 1 ppm FC overnight.

[Andyhl2]

Thanks for the responses. Pool Doc, I will hold off on the cya. Unfortunately, based on Chem Geek's experience, it may be a while before i add it. Chem geek, that is one very scary chart you have there. I am not looking forward to going through what you went through. It looks like I am going to need a truck load of bleach. Ugh.

[Watermom]

Not that it will help you now, but just reference in case you are ever in this situation again.

I, too, lost power on June 29 and it did not come back on until the evening of July 6. My solar cover blew off the pool and there were branches, twigs, leaves ,dirt all in the pool. I cleaned out as much debris as I could by hand but of course, could not get the dirt and bits of leaves out without a working pump as you noted above. However, we swam every day. We had to to stay cool as the daytime temps were over 100 and the temp inside my house was in the 90s. The bottom of the pool was dirty but the water was clean and clear. Every evening before I got out of the pool, I slowly walked all over the pool drizzling in a jug of bleach and then using arms and body to create lots of splashing and water movement to get the bleach mixed in. I did this each of the night while we had no power. In this way, I was able to keep the pool from turning into a green slime pit and in 100+ degree weather like we have been having, it wouldn't take long for that to happen!

Sorry you are dealing with this. If it ever happens again, you will know better what to do.

[Andyhl2]

It looks like I am on the right track. After getting no or very low chlorine readings in the morning for the past several days, I finally had a 6.5 fc reading this morning. Watermom, I hope it doesn't happen again, but if it does, I will definitely be following your technique. I thought about doing it, and in retrospect I should have, but I guess each day we kept thinking that this would be the day that power comes back. Thanks for the advice.