Green tint to pool after SLAM

[RecurveArcher]

The pool was clear on a Saturday, then green by Wednesday; not horrible, but couldn't see the floor drain in the deep end. I'm not sure how it got so bad so fast, but when trying to shock it, it was burning through chlorine. I had to put in enough chlorine to get it to what should have been around 55 so that it would stay above shock level until I could test it the next morning. I probably added about 70 gallons of 10% overall (generally one gallon will increase FC for me by about 2.5 ppm); had to add 10 gallons twice/day for a couple days to keep it above shock, while also running the SWG at 100% vs. typically it's at 20-35% to maintain.

It finally died off; turned off the SWG completely, stopped adding chlorine, overnight test has the FC staying steady now for the last few days, but there's still a green tint to the pool. You can't notice in the shallow end, but do in the deep end. I can still see the floor drain clearly now, and the water itself looks clear not cloudy, but it's not crystal clear and blue like normal. I've had to SLAM it multiple times before, but it always goes back to perfectly clear once the FC levels off, even with the chlorine still high, so I'm not sure what's different now.

FC: 27
CC: 0
pH: 7.2
TA: 200
CH: 150
CYA: 65
Salt: 3800
Temp: 90

FC is still really high, we have a cover, so it takes forever to come back down after shocking unless I replace some water, which I don't love doing on well. pH is low, but I believe that's normal with the FC so high. TA is always super high but I can't get it down and have read not to worry about it if pH is normal and it's not causing other issues. Whatever happened seemed to burn through the CYA as well, not sure if that's normal, but it dropped down to 0 and it decreased as well throughout the shock process. Salt got down to 3200, just added a few more bags a couple days ago.

I believe pH will come up once FC goes down, but I've never had an issue with green tint before with FC high. We are on well, but had work done on the pool last year and water trucked in afterwards to fill it. We topped it off with the well, and have used the well water to top it off a handful of times since then; the pool hose goes through the water softener, which uses iron fighter salt, so it's not great water, but minimal sediment and hardness. After draining some to close it for winter, re-filling, and topping off, best guess I'd say 65% of the water is what was trucked in and 35% well.

Reading some other threads it sounds like high iron in the water could be the cause of the green tint, bug again, hasn't been an issue in the past with 100% well water so I don't know what would be different now with only 1/3 of it well water. Regardless, is there a good way to test that, or what can be done about it? Metal remover products? Should I drain some and top it off (with well) to get FC down and see if that helps before doing anything else? Could there sill be a contaminant even if it's not consuming the chlorine anymore?

I'll also note that the floor drain does not work; well, it used to be clogged, got it un-clogged when the work was done last summer, but there appears to be a leek in the floor drain as air comes in if I open that valve. Here and there we get some water loss, I assume leaking through a broken floor drain pipe, which could be part of the issue of what caused the problem in the first place if contaminants are getting into the water through that, or the stale water sitting in that pipe. Regardless, circulation in the deep end isn't great.

 

[Texas Splash]

Well, let's stick to some basic and prioritize things so you don't get overwhelmed:
1. Check your PoolMath calculations. I know that a 1/2 gallon of 10% chlorine increases the FC in my 18K pool by about 2.5, so your 32K pool should need much more.
2. Don't worry about the TA right now. Your area is normally high, but it can be worked on later.
3. We'll worry about pH later as well.
4. Drain suction isn't a big factor. In fact, if it didn't work at all no biggie.
5. Iron, algae, or both? THAT's the priority. I would do an Overnight Chlorine Loss Test this evening. Algae must always be addressed first anyways. So let's rule that out first before worrying about iron.
6. However, since you are maintaining a SLAM FC level of 28 anyways, try capturing iron with polyfill now. Either in the skimmer or through a bucket, but try to grab as much as you can with the high FC level since an elevated FC level aggravates the iron and makes it easier to filter.

Let's start there and see how it goes.

 

[RecurveArcher]

Thanks. I think I found the thread those pictures might have come from, but I'm not clear how to use the polyfill or what specifically to buy. We have skimmers, with baskets, so do I just buy a bag of polyfill and drop some in each skimmer? I feel like the suction would pull it through the basket holes, but maybe not. A lot of what I see on Amazon for pools indicates it's a replacement for sand filters, or just generic polyfill stuffing.

I'll also add that on the line that goes to the pool house (and hose used to fill the pool), in addition to going through the softener it does also go through on of those big blue filters as well.

 

[Texas Splash]

You can buy polyfill from the fabric section ( I believe). If you are worried about it getting through the skimmer basket, place it in a laundry bag or paint straining net. Or as in the pics above run some of your water through a separate container with polyfill.