No chlorine in pool this morning, can’t figure out why?

[Mcaveman]

I have noticed my FC levels have been low this year and came out to zero chlorine about 10 days ago, I assumed it was the filters because I had seen the De not sticking so great to filters so I put in new and cleaned the IC40 chlorinater re tested the next day and the levels were better FC was at 2 and checked every day they stayed around 2 which for having my IC40 set at 50% those numbers still seemed low. Again this morning I came out to no chlorine in pool and that’s after bumping IC40 to 60% yesterday, all lights are happy on the IC40 and salt levels are 3400 ish. I am thinking about replacing the IC40, not sure what else to do.

FC 0
Alk 110
Ph 7.3
CA 300
Cya 90

 

[Mcaveman]

Also could I replace with a IC60? It’s a large pool around d 45k gallons.

 

[Jimrahbe]

Mc,

I doubt your IC40 is bad, it is a little small for your pool, but I suspect that you have algae, even if you can't see it yet.

You need to run an Overnight Chlorine Loss Test or OCLT... Overnight Chlorine Loss Test

Your main problem is running your FC at 2 ppm... An FC of 2 is below the minimum in most cases..

Tell us what your CYA level is... You should always try to maintain your "Target" FC per the saltwater section of this chart. FC/CYA Levels

Thanks,

Jim R.

 

[Mcaveman]

I updated original post CYA is 80

 

[Mcaveman]

I’m running the IC40 at a higher % than last year and still getting those lower FC numbers I assumed it was equipment related I never thought of algae.

 

[CrystalRiver]

At CYA 80, FC should never be below 4. Since you've been below minimum, and especially because you've been below minimum for and extended period of time, you almost certainly have algae.

You'll need to get several gallons of liquid chlorine, adjust pH to 7.2, and begin a SLAM. You can raise the FC level using liquid and do an OCLT tonight to confirm, but you have several indications that it's algae.

 

[Mcaveman]

I guess that’s better than needing a new IC40. Is it ok to swim during slam if water is clear and FC levels are in range ? Thanks

 

[CrystalRiver]

It's safe to swim as long as FC is not above SLAM and you can see the entire bottom of the deep end (so you would know if someone was drowning).

 

[Mcaveman]

The water got really cloudy after adding the bleach to bring to slam level, I don’t recall this happening last time I had to slam but that was years ago