My chlorine levels are weirding me out

[Abnaxis]

I opened my pool roughly 2 weeks ago.

I expected a green mess down there, but instead I found a detritus mess down there with zero green.

Upon testing, I found FC 14 in the water. According to Pool Math, it's supposed to be between 4 and 11 , so that's not too far beyond the pale except I haven't touched the water since last October. "This is what I get for having the local pool guys close for me since I was too busy," I thought.

Now, I WANT the chlorine to drop, because I have some iron stains on my pool from last year I want to wash off, and when I tried to use ascorbic acid on it last year without dropping chlorine levels first it didn't work. Except, I've had the pool uncovered for two weeks now and my FC is STILL 4.5. This means 1 of three things is happening:

1) I have lost all sense of what work it takes to keep this thing chlorinated since I converted it to saltwater. Before, if I wasn't pouring a bit of chlorine in every other day levels dropped to far, even if it was covered. Now I've had two weeks of filling my skimmer basket with tree buds and it's still sanitizing. CYA doesn't stabilize THAT much, does it? The waters still cold, maybe that's throwing me off?
2) I'm doing something wrong with the test kit. I've been doing this a while though but I never rule out human error with myself.
3) My test kit is too old. I'm still using the powder and titration solution I got like 2 years ago .

My bet is on #1 but I wanted to ask here because this is just really weird to me. At the same time, the whole reason I have iron stains to begin with is because chlorine got too high since I'm still trying to learn how to use the SWG after converting...

 

[mas985]

A FC of 14 to 4.5 over 14 days is about 8% loss per day which is low but not that unusual if the pool water temps are still fairly low. I have measured as low as 5% per day with low water temps and the sun low in the sky (winter).

What is the current CYA level?

What is the current water temperature?

Indiana in spring is fairly cloudy, correct?

 

[Abnaxis]

Yeah it's been pretty rainy and overcast, I've had to drain the water a couple times due to rain.

Still, I've had to dump a full skimmer basket every day from tree buds, I figured the bio-matter would use up the chlorine? Is the sun really responsible for that high a proportion of chlorine loss?

I'll report on current CYA and temp here in a minute when I have a chance to check.

 

[Abnaxis]

CYA is somewhere between 70 and 80.
Current temp is 65F, but I think it's been mid-to-high-50s for a lot of the last 2 weeks. When I put my hand in to take a sample out now it feels bracingly cold, before it felt bitingly cold.

 

[mas985]

There

CYA is somewhere between 70 and 80.
Current temp is 65F, but I think it's been mid-to-high-50s for a lot of the last 2 weeks. When I put my hand in to take a sample out now it feels bracingly cold, before it felt bitingly cold.

That combined with the cloudy days I think can explain what you are seeing.

On sunny days, UV extinction is the largest contributor to FC loss and even on cloudy days it is still there just not as much. Algae is probably the next largest consumer of FC but only if it gets out of control and is reproducing rapidly. Algae spores drop in the pool all the time but not a lot so it is fairly easy to kill these as they drop in and it doesn't require much in the way of FC. Bacteria and viruses are similar. General "dead" organic debris does not react with FC as quickly as the others and the oxidation process is fairly slow so in most cases you won't even notice this type of consumption.

 

[Abnaxis]

So it's really just losing 5%/day when it's chilly and cloudy? That's wildly different from when I was manually chlorinating

That'll be useful to know when I turn the SWG back on. I've been having a lot of trouble figuring out how to set the thing so FC doesn't go so high with the auto cover on I start depositing iron on the sides