Coral Compass Pro · $3/month · what's included
A pump rated 1,000 gph moves far less once it pushes water up to the display through pipe, elbows, and valves. Enter the lift, your plumbing, and a few points from the pump's head curve; the calculator adds friction for every fitting, finds where the pump curve meets your system's demand, and reports the real flow and display turnover.
The math
Friction (ft) = 0.002083 × L × (100 ÷ C)1.85 × Q1.85 ÷ d4.8655 (Hazen–Williams; Q in gpm, d in inches, L in feet, C = 150 for PVC)
Total head = vertical lift + friction
Fittings are converted to equivalent straight pipe: 90° elbow 30 diameters, 45° elbow 16, tee branch 60, tee run 20, open ball valve 3, swing check valve 100. Sch 40 PVC inside diameters are used (1" = 1.049 in).
Try it
Sample: 75 gal display, 1" Sch 40 PVC, 5 ft lift, 8 ft of pipe, four 90° elbows and a ball valve, pump rated 1,000 gph at 0 ft.
Fittings add 10.8 ft of equivalent pipe. Estimated real flow: 638 gph at 6.2 ft total head, display turnover 8.5×/hour.
Sources
- Hazen–Williams friction loss equation (US customary form); C = 150 for PVC
- Crane Co., Technical Paper No. 410, Flow of Fluids Through Valves, Fittings, and Pipe (equivalent length L/D values)
- ASTM D1785 Schedule 40 PVC pipe dimensions
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