Hi all. Please don't wait on me for offering up good suggestions as I'm not online a ton due to a work project right now
I actually like all the suggestions...including in this case perhaps flocking with alum if vacuuming to waste is a solid option.
But let's review, Allmar, to try to dx next steps: Correct any wrong assumptions -- in fact, please confirm each so people can see at a glance what the clue trail is
1. You have passed OCLT 3 nights in a row, meaning with FC above 10 after dark, you've lost less than 1 ppm before dawn each time. (For any suggestions below to be valid, this one has to be dead on accurate.)
2. However, the water is cloudy beyond 18" and appears to have a green tint, with sparkly crystals of fine particulate.
3. You removed copper pennies and a rusty bucket (iron) from the pool. There is visible iron staining on your steps. AND you're on a well...
4. You have a sand filter for which at the beginning of the season
A) a pool tech changed sand and replaced spider gasket
B) you or hubby changed sand and replaced spider gasket
(Please tell us which. If pool tech changed it, ask him what brand of sand. There has been a MIS-labelling event at a sand mfg this season, and while rare, its possible you got a batch that's finer than meant for a pool)
5. The pool store has told you you have no metals in your water AND that you have a TA of 10...when you yourself read 100
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Concerns:
1. I have no way to tell if your filter is actually functioning properly, though your psi rides roughly where mine does.
2. I can't "prove it" but I'm a monkey's uncle if you don't have metals in that water, if only from rotten pennies and a bucket...but being on a well, its highly unusual not to have SOME.
3. We have no way of knowing what products the former owners used, or if foreclosure (was it?) what kind of quick fixes a property marketing co. might have tried. Cloudiness/crystals could be from prior metal treatments combining with calcium, each other, sulphates etc.
Possible Proposed Next Steps - please understand this is just my best stab
1. Let your FC come down to 9. Test your TA and PH. Confirm that your TA is, say, not belw 50 or 60, and certainly not 10. If it really IS 10, adjust up. Adjust your ph to 7.2 if you plan (in a bit) to use Jack's, or to 7.5 or 7.6 if Metal Magic. (I would do this. See reason below.)
2. As Zea said, first let the filter try a bit more, try a slow vac after shutting off overnight to settle. Confirm that when you vacuum to waste, its going to waste and nothing's askew with the multiport via the spider gasket.
3. If by the weekend, the vacuuming and filtering has not improved clarity by 50% or more, AND vacuum to waste is working fine, then get some alum flock, apply per instructions of mfg per wrobert's suggestion, wait 24 hrs with pump off, and thoroughly, carefully, vacuum to waste.
4. You will need to top up with well water. If you have a reading on your well water for copper, iron and maganese, please post. But in this case, just to even clean the stairs, I'm going to bet two bottles of Metal Magic will be worth their weight in gold. If you use it, you will need to let FC drift down for initial application. So plan ahead.
If you want to see how much it will take to clean the stairs, check out the sponge test (I'll add link).
http://www.proteampoolcare.com/images/uploads/MetalMagicSpongeTest.pdf
5. After the above, at a min., if your filter is working properly and you have correctly sized sand, and no outbreaks of algae by maintaining your FC to normal range for your CYA except for the day you use the sequestrant, you *should* be in the clear.
If after doing the above, you clear (after floc) and then cloud slightly after sequestrant (you might for about 3 days), it suggests your filter isn't keeping up with metal removal.
But if your water clears from the floc, but then clouds back up for an extended period, I would be regarding the filter with suspicion
I know this seems like a complicated set of if-thens. I'm just trying to help you sort a way forward.