Filter Backwash Water Loss Estimator
Calculate how many gallons of chemically-treated, heated water you dump into the yard every time you backwash your sand or D.E. pool filter.
Technical Comparison
| Filter Type | Water Wasted per Cleaning | Frequency |
|---|---|---|
| Sand Filter | 100 - 300 Gallons | Every 2-4 Weeks |
| D.E. Filter | 50 - 150 Gallons | Every 1-3 Months |
| Cartridge Filter | Almost Zero (Hose off) | Every 3-6 Months |
Frequently Asked Questions
How often should I backwash?
Only when the filter pressure gauge rises 25% (usually 5 to 10 PSI) above your clean starting pressure. Backwashing too often wastes water and chemicals, and clean sand actually filters worse than slightly dirty sand.
Does backwashing lower my Cyanuric Acid (CYA)?
Yes. If your pool is 10,000 gallons, losing 200 gallons in a backwash removes 2% of your entire pool water, effectively lowering your salt, CYA, and Calcium by 2%.
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