How much chlorine loss is normal?

[dubbedout]

I've been testing my water nightly ever since switching to bleach. I've noticed that it seems to me that I'm losing chlorine quickly. Maybe it's normal but I wanted to run this past the experts!

Last night @ 9:40pm
FC - 14

Tonight @ 7:50pm
FC 9.5

I'm in AZ where it's consistently been over 110 degrees lately. My CYA (last time I tested) was at 117. The pool is crystal clear, but should I be losing that much CL in 1 day?

[Watermom]

How did you get a CYA reading of 117? The 'disappearing black dot' CYA test cannot differentiate readings past 100.

Did you add any bleach after you got the reading of 9.5ppm?

[dubbedout]

When I tested using the K2006 kit it was right under the 100 mark, so I took a sample to the local Leslie's and had them test it to get a better idea of where it was. They got a 117 with their digital test. I haven't added anymore bleach yet, I usually do around 9:30pm as thats when my pump turns on.

[Watermom]

Ok. Then, if you can, go out in the morning and test the chlorine within one hour of sunrise and report your reading. If you lose more than 1ppm overnight, then your chlorine loss is probably from fighting something in the water. Also, test the CC in the morning. How does the water look?

[dubbedout]

Water is crystal clear, and CC is always either 0.5 or 0. I just fought off some algae last week, thats when I switched to bleach. I'll test in the morning for chlorine loss overnight.

[dubbedout]

Ok so this morning FC is 9. Water still crystal clear. What's the deal?

[Watermom]

Since you only lost 0.5 chlorine overnight, that is good. It is normal to lose chlorine to the sun, but when you lose large amounts overnight when there is no sun, it is an indicator that you are fighting something. Since you lost less than 1ppm, it tells us that it is pretty certain that you have that algae bloom licked. But, you do need to add chlorine this morning. With your CYA level, you must keep the chlorine between 8-15 ALL THE TIME. If you let it drop below that, an algae bloom will start.

You don't show your volume, so I can't comment on bleach amounts. But, if you go to the Forum Q & A section, there is a thread called 'Bleach Calculator.' I think it is in the third post in that thread, there is a link so you can download a calculator. It has more than just a bleach calculator. In the upper left hand corner, there is a drop down with other calcs as well.

What you want to do is add enough bleach to get back up to 15. Then, test tonight. Again, add enough bleach to get back to 15. Then, tomorrow evening, see where you are when you test. If you are below 8, then you will want to take it just a little higher. My guess is that if you add enough bleach to get to 15, you should be able to make it a couple of days without adding more bleach. That is one benefit to having a high CYA pool.

I'm hoping that your chlorine loss will slow down and that your higher usage the other day was just a result of the recent algae bloom you were fighting. The key is that you can never let your chlorine drop below 8ppm.

Keep us posted how things are going and let us know if you have further questions.

[dubbedout]

Thanks Watermom! I have a mac so the bleach calculator doesn't work for me but I've been using www.thepoolcalculator.com to help calculate my chemicals and it seems to be working.

Btw, How do I get the standard signature with all my info on there? I remember filling out a google doc when I first signed up last year but never showed up for my sig.

[Watermom]

You can add it yourself and that would be a big help if you did. Go to settings (upper right near where you log in) and then click on create a signature. (or something to that effect). Please put type of pool, volume, size of pump, type filter and that you have a Taylor K-2006.

[dubbedout]

Ok, here's a little update.

On 6/26 my FC was 9ppm at 8am so I added 2 gallons of 8.25% bleach, I tested again at 10pm and it was down to 11ppm so I added another gallon. Then today I tested at 730pm and have FC at 10ppm.

So, as it looks I'm going through about 2 gallons a day to keep it above 8ppm due to my CYA being over 100. Water is still crystal clear so I'm assuming all this CL loss is due to the wonderful heat of AZ.