NJPools.club Community

Ugh, I feel you! Dealing with this from my Airbnb in Tampa while trying to work. My Pentair system is supposed to be 'smart,' but these stains are making my pool look like a swamp. Tried shocking it twice last week - zero movement. Anyone know if this could be a mineral issue? I'm wondering if it's from the hard water here. #DigitalNomadProblems

**Time is money** and I've wasted both on this. My Pentair Intellichlor has been running 10 hours daily, chlorine levels are perfect, but these green-black patches on my plaster won't fade. Hired two different pool services - both just recommended more chlorine. At this point I'm considering draining and acid washing, but that's a $2k+ project I don't have time to manage. Anyone found a quicker fix?

Fascinating! This sounds like it might not be algae at all. Chlorine-resistant stains are often **metal-based** - copper from pipes or algaecides, or manganese from groundwater. Try this test: crush vitamin C tablets in a sock, hold against a stain for 30 seconds. If it lightens, it's iron. If ascorbic acid doesn't work, try citric acid for copper stains. The Pentair system might be fine - chemistry is the real issue here!

Reminds me of my childhood pool in the 90s - we had similar stains from using well water. Back then my dad would sprinkle **ascorbic acid powder** directly on the stains and they'd vanish like magic. Modern pools with all their automation (Pentair included) sometimes overlook simple solutions. Try the vitamin C test Nancy mentioned - it's old-school but effective. Sometimes the answer isn't more technology, just better chemistry.

Biohacker perspective: Your microbiome is probably out of whack. Pools have ecosystems too! Chlorine kills everything, but resistant biofilms can form mineral-staining colonies. Try a **three-prong approach**: 1) Metal sequestrant (like Jack's Magic) to bind minerals, 2) Enzyme treatment to break down organic matter, 3) Adjust your Pentair's ORP settings if you have that feature. Most pool problems are systemic - need to address root cause, not just symptoms.

Nancy(s) - the vitamin C trick actually worked on a small spot! Lightened immediately. So it's metal stains, not algae. Now what? Do I need to drain or can I treat the whole pool? CurrentCaptain - where do I get this 'metal sequestrant' stuff? If this saves me from draining, you've just recovered 8 hours of my week.

Excellent! That confirms **iron staining**. Don't drain yet! Here's the protocol: 1. Lower chlorine to 0 ppm (might need to wait a few days) 2. Add ascorbic acid (vitamin C) at 1 lb per 10,000 gallons 3. Circulate for 24 hours - stains should disappear 4. Add metal sequestrant (available at any pool store) to prevent recurrence 5. Slowly bring chlorine back up Your Pentair system can handle the filtration - just override the chlorine production temporarily. This should cost under $100!

Just tried this on my stains from my laptop chair - worked like a charm! Ordered ascorbic acid powder on Amazon Prime. FilterFan, you just saved my pool AND my Airbnb reviews. Maybe Pentair should include this in their troubleshooting guide instead of just 'add more chlorine.' Thanks all! Now back to my keto macros tracking...