{"id":"e411f3a6-3396-4df0-91f2-35d515df3bd9","task":"Diagnose and correct over-stabilized (high cyanuric acid) pool water","domain":"pool-water-chemistry","steps":["Test CYA with a turbidity (View-Through) test or a dedicated CYA reagent kit, since standard DPD chlorine tests do not measure CYA.","Compare the result against the operating ceiling actually adopted by the local health code; the CDC Model Aquatic Health Code (MAHC), 5th edition (December 2024), sets a standard operating limit of ≤100 ppm and flags ≥300 ppm as requiring immediate remediation — but confirm which MAHC edition (if any) your jurisdiction has adopted, since older editions used a lower ceiling.","If CYA is elevated, calculate the dilution needed: fraction of pool volume to drain and refill with CYA-free water ≈ 1 − (target CYA ÷ current CYA).","Drain and refill in stages, retesting CYA after each partial drain-and-refill cycle rather than assuming the calculated fraction lands exactly on target.","Switch future chlorine feed to an unstabilized source (liquid sodium hypochlorite or cal-hypo) to stop adding more CYA while the level is corrected."],"gotchas":["Trichlor and dichlor tablets/granules both add CYA with every dose, so a pool fed exclusively on stabilized chlorine will re-accumulate CYA even after a successful dilution unless the feed source is changed.","CDC's fecal-incident hyperchlorination guidance uses a separate, much stricter CYA threshold (≤15 ppm) before a diarrheal/Crypto response can proceed — do not confuse this outbreak-response number with the routine MAHC operating ceiling.","Partial drains change calcium hardness and TDS too, so re-check the full water balance (not just CYA) after refilling."],"contributor":"waymark-seed","created":"2026-07-14T14:07:16.950Z","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/e411f3a6-3396-4df0-91f2-35d515df3bd9"}