okay! Thank you for your help! No- I’ve never used Cal-Hypo. i haven’t been overly concerned with the hardness because I rarely, if ever, have any scale (or stain) rings.
To be honest, I had no idea about this whole ‘metals dropping out of solution’ thing.
I’ve had smaller pools than this one for years- ( ie. 18’roundx52”) and I have ALWAYS had beautiful crystal clear water- no algae, no stains, nothing.
The ONLY thing I did with them was floating chlorine pucks!!! I did the simple chlorine/pH drop test and they were both always perfect.
Last year was my first full summer with the pool (it was installed the previous fall).
No problems with stains.
Late in the season I bought a Floating Solar Ionizer (Do you know what I’m talking about?) I’ll attach pictures. This ionizer was supposed to eliminate/prevent formation of algae, and reduce chlorine demands. It has a copper rod in it. I thought this might be a great thing- reducing the need for both algaecide and chlorine.But because of my inexperience and lack of knowledge about metals in pool water & chemicals I’m afraid that might be the source of the staining

I posted pictures of it previously asking if anyone thought it might be the cause…but no one replied

)
So, I closely examined the stains to determine what colours were present to help determine what they were. They looked like iron to me- not copper- so I treated with the easiest method first (AA).
It did lift and lighten the stains, but even after 2 applications, & scrubbing with a brush & Mr.Clean eraser, there were outer rings still apparent, and there were tiny circles of black scattered about (looked like the paper circles you get out of a 3 hole punch).
So…I thought blackspot algae, and treated it twice with algaecide.
Questioned the possibility of sulphur.
So I’m down to two remaining possible causes (neither of which I like

)
1) The solar ionizer?(which I took out weeks ago)
2) There’s only one other possibility- and I don’t know if it’s even plausible…but I’d like to hear thoughts….
I live on a floodplain. There’s a very high water table, and the water doesn’t ‘always’ overflow the river banks ( often it does) or reach my pool (but sometimes it does.)
2017 there was a massive flood and my property was basically the ‘funnel’ that it went through- my property sustained the most damage of the entire flood. (river rose 23’ and came through my entire 4 acres at 5’ deep

- over top of my 52” pool - & tractor cab!)
I’m hoping that was THE once-in-a-hundred-year flood & i never seen anything like that again, but I wanted to try and make this pool as stable as possible (the other flood actually went UNDER the foundation of my house, moved the soil, cracked the foundation, and the house is shifting). So, anyways…
This is how I did the foundation:
•the ground beneath is clay.
•We used a tripod laser level every step of the way.
•Dug out about 8” and packed with 6 inches of stone dust /or pea gravel - it’s called different things, but used a compactor and made it like cement.
• After a few weeks, put Landscape cloth down to stop weeds.
•then, I got THICK rubber conveyor belting, siliconed the joints in between the strips, and made sure everything was perfectly flat.
•put 2” rigid styrofoam sheets. (Long story but I had driven for hours to get these because the guy had assured me they were totally smooth & would be fine under the liner. They weren’t. They had bumps and air pockets, but it was October by then so I just took them. I filled the holes with an adhesive/epoxy/caulk kind of stuff and sanded them (stupid amount of work

I know

)
•put the Felt Gorilla pad down, then pool sides, cove moulding & liner.
•everything was completely dry when we put each layer down and installed the liner.
SO…now I am wondering if there is any possible way the problems could be coming from BELOW the liner. I can’t see how they would be…but I’m not experienced enough to know. Even if they WERE coming from there, I would assume they would be ORGANIC stains, so the AA and/or the algaecide SHOULD have dealt with them, correct? The stains are around the far end of the pool (opposite from the skimmer & return outlet which are both on the left corner closest to the deck ), then they are up the right side and around the right corner closest to the deck- all the areas which have the least amount of flow, so it would make sense that metals would be dropping out of solution in those places. Also- they are ONLY on the floor- nothing on the walls, & only twice have had a very faint greyish ring that wiped off easily with my hand.
Based on the stains, treatments I’ve done, etc…. What are your thoughts???
I am leaning towards these stains being copper related…but to me, they didn’t/dont look like copper stains- they didn’t have the same appearance or colours as that photo examples I saw.
Do they look like or sound like copper stains to you???
I REALLY appreciate you taking the time to read through all this Texas Splash!! (And anyone else as well!!) And I’m grateful for your input!!! This quite a learning curve- that I never expected! Any thoughts on how I should proceed with the stains (after I get things levelled out and I get guidance SLAMMING it. )

I wanted to work on building a solar water heater this summer

but I’ve spent all my time trying to get this straightened out. I think I will go ahead and get those filters that can be attached yo the hose. The hoses can be hooked onto a small portable pump and the water in the pool recirculated through them, so any metals should be removed and maybe I can start from fresh. Thanks again for your help. Pictures below of the Ionizer - (don’t remember how it works exactly but I’ve included before & after pictures…)
Patti