Pump & irrigation flow rate calculator
A pump has to satisfy two demands (turning the reservoir over for oxygen and mixing, and feeding every emitter at once) and it has to do it at height, where its rated GPH has already fallen off.
System demands
Result
Includes a 1.2× wear & clogging factor
The friction allowance is a flat estimate, not a hydraulic calculation: long runs of narrow tubing, drip manifolds, and venturis can lose far more. When in doubt, one pump size up costs a few watts; an undersized pump starves the far emitters first, silently.
Now that the water moves, what's in it? Solve your nutrient recipe →
How do you size a water pump for a hydroponic system?
Add your reservoir's target turnover rate (how many times per hour you want to cycle the full volume) to your emitters' combined demand at full flow, then account for head height, since every foot of vertical lift reduces a pump's effective GPH. Undersized pumps starve the highest emitters first. Enter your reservoir size and emitter count above for the GPH rating to shop for.