This article will help you diagnose and troubleshoot your Nutritower pump.
here are some easy steps to follow:
1) Check the water level to make sure it is at least 2 inches above the pump
2) Check water tube length - The pump should be sitting flush at the bottom of the reservoir.
3) Unplug the pump from the timer and plug it in directly to the socket and check for noise
4) If there is no motor sound at all, replace the pump - it is burnt out or defective
5) Check flow rate valve at the front of the pump is at max
6) Clean the pump and remove any residue or algae accumulated
7) If the pump motor is running, unplug the pump and remove the cover to expose the impeller casing
8) remove the impeller facing and the impeller
9) Inspect the impeller - if it's broken, replace the impeller reassemble, and check the flow again.
10) If the impeller is intact, replace the impeller and cover and detach the main water line.
11) Place the pump on its side in the reservoir and plug the pump back in. if water pressure is good from the pump, try holding the pump submerged and placing the water line loosely back on the pump repetitively to flush water up and down the tube.
12) Replace water line temporary and observe if any flow
13) Blow in the tubes where no water is coming out and repeat the flush process
If there is no improvement, please follow the procedure to inspect the manifold found here.