Can't figure out where the chlorine is going!

[liulady]

So, I am just SO frustrated! I found TFP last year and I've been a convert from that time forward. My little AG pool was perfectly crystal clear for the rest of the year last year.

This year, I was SO confident! I knew what to do and it was such a relief. Well, I feel like I'm back to square one again. This is a brand new pool as our old one had too many leaks in the liner. So, fresh new water and new pool. The only "carry over" from last year is the pump and filter housing.

As we live in hot and sunny northern CA and the pool is in the sun all day, I have my CYA at 55. But, I have still lost about 6 ppm per day of chlorine. I didn't do an OCLT until I noticed a couple of algae spots on the floor of the pool. And, then I realized I had a problem.

I immediately scrubbed it all down and started a SLAM. The water has been clear all along and I've never had more than .5 CC, so I assumed that this would be a quick and easy thing to turn around. Unfortunately, it isn't. I have yet to pass the OCLT. In fact, I usually lose 6+ ppm per night. I lose 9+ ppm every time I test during the day! Since I have fairly high CYA, my slam level is around 24. It is dropping to 11 and 13 during the day.

Since day 2 of the SLAM (today was day 6), the water is not just clear, it is CRYSTAL clear and sparkling. I have checked everything for hidden algae...its just a tiny AG pool after all? I apologize for the rambling message, but I'm just SO frustrated! Shouldn't I have at least a little CC with that much chlorine loss during the day and night?

 

[MarianParoo]

Not necessarily. CC's aren't the only indication of a problem. If you have truly checked everywhere, your slam should go quickly. BTW, for PoolMath, round that CYA number up to 60. How often are you testing and adjusting?

 

[liulady]

It depends upon the day and what else is going on...I always check first thing in the morning and bring the chlorine up to SLAM level. Then, I check again around 10...noon...5 and then again after the sun goes down. Each time bringing it back up to SLAM level. It has usually dropped at least 5 ppm. That's at a minimum.

I guess, I am getting hung up on the fact that the water LOOKS perfect. I've cleaned the ladder, skimmer, filter cartridge housing and replaced the cartridge with a brand new one just in case. Just can't figure out where the problem causing a massive chlorine loss could be hiding.

 

[MarianParoo]

Just a thought here... What is your actual water depth?

Here are two scenarios with a CYA of 60 and corresponding shock level of 24

1) your reported volume of 5,000G:
To raise FC from 12 to 24 requires 2Q, 3C of 8.25% bleach.

2) your reported depth of 48" which gives a volume of 6,000G:
To raise FC from 12 to 24 requires 3Q, 1C of 8.25%.

If your pool is really 6,000G and are dosing at 5,000G, your add would be short of hitting your slam level by 2-3ppm.

Again, just a thought.

 

[liulady]

Good catch! Actually, though, I did have it plugged into pool math as 6K. I just had it wrong in the signature.

I lost 3 ppm overnight. Dropped from 24 to 21. The only thing that I have not yet done is completely open up the filter and strainer basket and bleach everything out. I have cleaned things here and there and replaced the cartridge, but maybe something is still lurking? Just so strange that I'm losing SO much.

I am glad that the pool itself looks beautiful, but with 100 degree days coming next week...I'm just asking for trouble if I can't get this figured out!

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This might be a silly question, but is it possible that a smaller body of water...ie. my little 6K gallons pool...would lose chlorine at a faster rate than a much larger pool? I know that wouldn't explain the overnight chlorine loss, so I know that I have a problem, but it might explain why I was losing 6 ppm+ daily from the start?

Clearly grasping at straws at this point...