You really need to stop adding stuff to the pool, its wasting your money and not solving anything since you have not found the culprit yet. I would rather wait until your test get in and retest both fill water and pool water, because At this point I would start suggesting a clean start, that means draining(tarp method) and no sequestrates in the water. Im really hoping you can solve this.
Felipe
Maybe easier said than done when I've been looking for the culprit for 3 years now. Just this season, I drained over half the pool immediately after an AA treatment hoping to drain the metals in suspension.
I've had the source water and pool water tested for metal repeatedly and I'm always told there are no metals found.
I would love nothing more than to stop depending on stain treatments and metal sequestrants but I can't stand to see the liner turn from blue to beige to brown while I ponder the possibilities.
Me and everyone I've asked for help can't come up with what the source of the problem may be. Here are the steps I've taken over the past 3 seasons trying to identify the issue.
1. Stain treatments followed by sequestrant.
2. Multiple inspections of all metal fasteners (skimmer screws etc).
3. Multiple inspections of pool light, removal of pool light, to look for any metal corrosion.
4. Replacement of stainless steel ladder (year 1 of 3) and replaced it with a Saftron polymer ladder after finding some corrosion/rust on the ladder rung screws.
5. Installation of a sacrificial zinc anode (bonded to pool equipment and buried in moist soil as suggested here by Chemgeek).
6. Several rounds of water testing, both my own and pool stores, labs...looking for metals.
7. Used Jacks stain ID kit to identify type of stain. The test seemed to indicate iron staining.
8. 2 seasons of draining about a third of the pool water with a pump and this season I drained about half the water (almost ruining the liner in the process as it started to shrink).
9. Hired contractor to replumb equipment so I can completely bypass the pool heater from all water flow when we're not actively heating the pool.
10. Banged my head against an assortment of hard surfaces.