PitCritter

Can you double check that? What's a couple of zeros? Make that 18g/10,000L will lower chlorine reading by 1ppm. That'll teach me not to try to calculate during the last hour of a 12 hour night shift. Oh well, no difference anyway, the pool will be drained and re-filled by morning. Then we'll see. Quantum, thanks for the test suggestion, but I think I'll just cut my losses on this one and start from scratch. I'll post back in a couple of days what the outcome is. I'm off until night shift on Jan 1 after tonight.

I just finished doing a quick check of our chemical inventory. One interesting note...a 25kg pail of "ProGuard Chlorine and Bromine Neutralizer" made by Asepsis Inc. It's about half full. 12.5kg of this stuff could definitely put a dent in CL levels. The directions say that 18g/100L will lower residual by 1ppm. My pool is just over 50,000L. 12.5 kg would lower residual by +/- 140ppm by my quick calculation. It looks like it's time to drain/re-fill and lock up the remaining half pail. Is there a test for this stuff?

Thanks for the detailed reply so far...

I recently inherited the upkeep and maintenance of a small pool in the hotel I work for. Up until now, we've had a company take care of it for us so I don't know a lot about the history. Immediately prior to taking over the pool, we had a contractor install a saltwater CL generator to make our upkeep a little easier (theoretically). Here's the problem: Although my pH, salt level, hardness and TA are all within normal parameters, I can't get the generator to keep up. The pool is only 14,500 gals, and the manufacturer's rep for the generator claims that it's of a sufficient size to chlorinate a pool twice that size. There is no stabilizer in the water, it's illegal in indoor pools in my jurisdiction (Ontario, Canada). The amperage on the generator looks like it's working at peak efficiency. If you look at the cell, it's bubbling furiously. Unfortunately, I can not detect nearly enough CL in the water. I have been adding a gallon of liquid CL overnight to get the levels up to something acceptable (3.2 or so), but the level drops off during the day to effectively zero by the time the pool closes 16 hours later. I have checked for and treated sulfate in the water although even when my level was only around 200ppb I had the same problem. Even if the generator is undersized, I should be able to detect some CL in the water. Even running it at 100% for eight hours overnight (while the pool's closed) generates no measurable CL. The salesman from the generator wants me to empty and re-fill the pool. I told him I would if he could explain to me why I was doing it. He told me, "There's something in the water that we can't test for, it's the only explanation". I don't buy it. I'm not saying sabotage isn't a possibility (remember we just fired a maintenance company), but I find it unlikely. Does anyone here have any ideas what may be causing my problem? I understand that Sodium Thiosulfate is added to a pool to lower CL. Is there a possibility that it may have been added by someone? If so, can it be tested for? Any and all ideas are welcome and appreciated.