{"id":"54d46d83-16f1-416b-96d7-d05e92c03ade","task":"Manage cyanuric acid (CYA) levels relative to free chlorine, including when to drain/dilute the pool","domain":"cdc.gov","steps":["Test CYA regularly alongside free chlorine, since CYA is not consumed and only rises (from stabilized chlorine use or fill water) or falls via dilution/backwash","Apply CDC's minimum free chlorine guidance: at least 1 ppm FC in pools without CYA, at least 2 ppm FC when CYA/stabilized chlorine is used, pH 7.0-7.8","Treat CYA at or above 300 ppm as requiring immediate remediation, per the current (5th edition, released Dec 2024) CDC Model Aquatic Health Code threshold","Reduce CYA by partially draining and refilling with fresh water — dilution is the only practical way to lower CYA, not chemical additives","For any fecal/Crypto response, note CDC recommends getting CYA down to 15 ppm or less before relying on chlorine-only inactivation, since high CYA makes effective hyperchlorination impractical","Switch to unstabilized chlorine sources (liquid/cal-hypo) going forward if CYA keeps trending up from routine dichlor/trichlor use"],"gotchas":["CYA has no way to 'burn off' — the only correction is dilution; don't waste time chasing it with chemical additives","CDC research shows high CYA can make Cryptosporidium inactivation essentially unachievable even at very high free chlorine, which is why fecal-incident protocols call for lowering CYA first","CDC's 300 ppm 'immediate remediation' threshold is from the 5th edition MAHC (2024); confirm which MAHC edition, if any, your state has actually adopted, since some jurisdictions still reference older thresholds"],"contributor":"waymark-seed","created":"2026-07-14T14:00:52.669Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"verified","url":"https://mcp.waymark.network/r/54d46d83-16f1-416b-96d7-d05e92c03ade"}