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Hey there! As a fellow vinyl pool owner who avoids harsh chemicals, I totally get your confusion. That purple reading on AquaChek strips usually indicates **very high calcium hardness** (like 1000+ ppm). For vinyl pools, we don't need much calcium since there's no plaster to protect, but Midwest water can be naturally hard. Have you tested your tap water? It might be the source. I'd recommend getting a liquid test kit to confirm—strips can sometimes be tricky with color interpretation. Also, check if you've been using calcium-based products accidentally.

**Quick take from a fitness pro who maintains a pool for post-workout recovery:** Purple = high CH. But here's the thing—for vinyl pools, high calcium isn't usually harmful like it is for concrete. It can cause scaling though, especially if your pH or alkalinity is off. Before you panic, test your other levels (pH, TA, FC) because balance matters more than one reading. If everything else is stable and your water looks clear, you might just monitor it. If you're seeing scale on walls or equipment, consider a sequestrant or partial drain/refill with softer water.

*Sips coffee while typing* Okay, so I had this EXACT issue last summer! Purple had me freaking out until I realized: **AquaChek strips can show purple if the test pad gets wet before use** (like from humid air or sweaty hands—midwest humidity, amirite?). Also, if the strip isn't read at exactly 15 seconds, colors can shift. My advice: 1) Store strips in a dry place, 2) Use a timer, 3) Compare to the bottle's chart in natural light. If it's still purple, Cathy's right—check for scale. But don't overcorrect; vinyl is forgiving!

Digital nomad here—I've managed my vinyl pool remotely! Data point: Purple on AquaChek 7-way strips typically means CH > 1000 ppm. Since you're in the Midwest, hard water is common. **Practical steps:** 1) Verify with a pool store test (free usually) or a Taylor K-2006 kit for accuracy. 2) If confirmed high, calculate a partial drain (maybe 25-30%) and refill with softened water if available. 3) Long-term, consider installing a water softener for fill water. Don't stress—vinyl pools don't require CH like plaster, so this is more about preventing equipment scaling than pool damage.

Adding to Nancy's point about testing—**avoid pool stores that push unnecessary chemicals**. Ask for a printout of all levels. If CH is truly high, a partial refill with rainwater (if you collect it) or softened water is the most natural fix. Also, check your total dissolved solids (TDS); if that's high too, draining might be wise. Remember, in vinyl pools, calcium doesn't corrode surfaces, but it can make water feel 'hard' and clog filters. Go gentle!

**Efficiency update:** If you confirm high CH and decide to drain/refill, do it gradually to avoid vinyl liner shifting. Also, test your fill water first—if it's already hard, mixing won't help much. For maintenance, keep pH 7.2-7.6 and alkalinity 80-120 to minimize scaling. And hey, if your water is balanced and clear, high CH alone isn't a workout-stopper. Just watch for cloudy water or scale buildup on heaters/pumps.