For real, what's going on with my chlorine level?

I'm confident in the testing overall. Unfortunately, the ammonia test kit arrived late, and I wasn't able to test it until right when the SLAM started. It did detect some ammonia. I suspect it would have measured higher with normal chlorine levels. Although I know I didn't get a good test, the fact that it did detect (some) ammonia a day into the SLAM is telling. I think, anyway.

Today looks good. I added 3 pounds of CYA in a sock yesterday for a 20 ppm increase. Today, the sock is empty, and CYA measured at 60. (That's the fastest I've seen it increase when adding stabilizer).

SWG at 50%, Fc at 12. That's also a good sign it is still holding chlorine.

I really think those two uncirculated lines might have been the root cause. The bypass line was literally a fully open return nozzle (with 100+ feet of pipe behind it), but hasn't been circulated in a year! When I first opened the valve, the water that came out was definitely murky. The second line was the vacuum suction port. It had a flapper on it. I replaced it with a screw in plug yesterday and in inspecting the flapper assemble, I held it upside down, filled the back with water, and it quickly drained through the "closed" flapper. So it was definitely not sealed. I don't know how much that would have contributed, but it couldn't have helped.

Lastly, I am still working through the Intellicenter bug issues. I know there are situations where it incorrectly turns off the pool relay (which powers the SWG but not the pump). I haven't gotten a repeatable chain of events that causes it, but it does periodically (but not often) happen. So running half a day or so without the SWG at random times also couldn't have helped.

Fc at 11.5ppm, lowered SWG to 20% for now to lower it some more. I am going to try to keep Fc at the high level in the CYA/Fc chart to give me a buffer.

Fc At 9ppm today. SWG set to 60%. Let's see if it holds!

Great results today. SWG at 60, running only 10 hours, Fc started at 9ppm and tonight it's 11ppm. Was a bit overcast today, but CYA is only at 60. So it looks like the SWG can easily handle the required chlorine requirements.

So the pool has been at 10 to 11ppm since Wed. with SWG at 60%. II know this is a bit high given my CYA level, but things have been holding so I left the SWG as is. So far so good, BUT, something happened today and I want to make sure everything is still good... This morning the pond behind my pool smells awful. A very seaweed type smell. The whole pool area smells of it, and it's been very windy. This morning the Fc was 10ppm. 12 hours later, Fc is now 7ppm, and Cc is now 2ppm. Haven't changed the SWG setting, but this is the first time Fc as dropped since before the SLAM. Should I ignore this since 7ppm is closer to what the chlorine/CYA chart says anyway, or should I add a bit more shock given that these changes may indicate a potential algae issue is on the horizon?

Thank you for the reassurance. I was just getting used to the stability, so the sudden deviation threw me. But I guess they call it water "balancing" for a reason!

I just remeasured CYA and it came in at 50. I was expecting it to be 60. Not sure if this is a measurement issue or if I did lose another 10ppm. I added another 2 pounds which should get me to 70.

Today, CYA was clearly @ 70, which is what I calculated at my last addition. Fc was way too high (15ppm). SWG was at 60%, so I've lowered it. I'm still trying to find the sweet spot between it vs. my pump run time. So far though, everything looks good. Lesson learned, make sure EVERYTHING gets circulated. I'm also a bit closer to zero-ing in on the Intellicenter "bug" that occasionally turns the SWG off.

It's been about a month. I can say that the SWG is now keeping the Fc at the correct level at around 55%. I haven't made any CYA additions, and haven't lost/added any water (and my salt has also been the same level). However, my CYA is currently at 50 (down from 70 a month ago). So I'm going to add another 2 pounds.

Pool temps have been about 90.
Fc has been a bit high since it took me awhile to get the SWG dialed in (I've been slowly lowering it). It's been closer to 12ppm on average.

So maybe between the temp and the high chlorine, it explains the CYA loss.

Mdragger88 said:

Bravo

Click to expand...

Thank you very much for all of your help!

As an update, I have been keeping chlorine slightly higher than recommended (It took a while to drift down, and for me to dial in the SWG %). Here's something interesting...

I noticed that the chlorine level kept rising! (It would drift from 10ppm to 14ppm) requiring me to continually lower and lower the SWG runtime, and eventually reduce the filter pump runtime by 1.5 hours too! I think this is a good thing, and also indicative that my chlorine was really working hard to eradicate nasties. I'm now down to 7.5 hour pump time with SWG at 50% and it's still at 10-12ppm chlorine with a tendency to rise. I may need to drop the SWG further.

CYA between 60 and 70. (Current CYA demand is about a pound a month to maintain).

All good news in my mind and the best the pool has ever been.

In case this thread helps anyone, I wanted to give an update after nearly 3 months...

I continued to lose CYA for August and most of Sept. However, for the first time since the pool was built, I turned off the heater. Normal temperature range was 90, but we let the attached spa get to 100 often and it is fairly big (about 1/15th the size of the pool). So average pool temp was probably around 92. With the heater off, pool is now 74 degrees.

No CYA loss at all. Chlorine is around 8ppm with the SWG at only 18% and pump run time reduced by 2 hours. I'm not sure how much the hidden algae or the high water temps contributed to my chlorine and CYA loss issues, but I suspect it was some mix of both.