Bad Sand Kills Carnivorous Plants: Test Before You Pot

"Washed" sand can contain limestone or marble, leaching calcium into the soil. This raises TDS to 150-200 PPM and pH to alkaline—deadly for carnivores. The mineral deposits on your pots confirm it.

Repot immediately into 1:1 peat/perlite. Perlite is predictable and widely available. Volcanic pumice is a great alternative where accessible. Sandblasting sand (pure silica) works but is expensive.

Your heavy top-watering helped flush some minerals, but the sand remains a long-term hazard. Don't risk your collection.