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🧪 Water chemistry
Pro toolkit
Langelier Saturation Index
LSI = pH + TF + CF + AF − 12.1 (TF = temperature, CF = calcium hardness, AF = carbonate alkalinity factors). Target about −0.3 to +0.3. Negative = corrosive (etching, metal staining); positive = scale-forming.
LSI = pH + TF + CF + AF − 12.1 (TF = temperature, CF = calcium hardness, AF = carbonate alkalinity factors). Target about −0.3 to +0.3. Negative = corrosive (etching, metal staining); positive = scale-forming.
LSI calculator
Pro essentials
Chlorine and CYA: Higher CYA means a higher free chlorine requirement. Many pros use a minimum FC of roughly 7.5% of the CYA level for non-SWG pools (and often higher for SWG-style maintenance), and track a separate shock level.
Variable-speed pumps: Affinity laws say power drops roughly with the cube of speed. Halving speed can cut energy use to about one-eighth, which is a strong selling point for clients. Always confirm minimum flow for heaters, SWGs, and cleaners.
Filter care: Record clean pressure at install. Cartridge filters need regular cleaning; DE and sand have their own schedules. Cartridge elements wear out, so replace as needed.
⚠️ Professional note
Local codes, licensing, and manufacturer specs govern. Verify ranges against current standards (e.g., your health department, ANSI/APSP/ICC-11, and equipment manuals).
Local codes, licensing, and manufacturer specs govern. Verify ranges against current standards (e.g., your health department, ANSI/APSP/ICC-11, and equipment manuals).