Regulating rate flow on pump
I have a pond system which consists of two separate ponds: one 5' x 4' (1.5'd), and the other about 10' x 7' (2'd). They are connected by a "stream" about 5' long (2"d). Also, there is a water fall, about 2' about water level, and a length of about 25' from the skimmer to the waterfall. Both the skimmer and waterfall have simple filters attached which help keep the water clean. I have calculated the entire capacity at about 750 gallons.
When the pond was installed, they put in a Tsurumi 50PN-2.4S (4PN) pump, which has a rate flow of 4740GPH. They put this in with the explanation that this flow was needed to keep water moving rapidly over the stream, and to give the waterfall a more "real" affect.
I am finding that this flow is too large for this pond. It is very difficult to keep the water level high enough in the larger of the two ponds. The results is the pump running low on water, forcing it to shut off many times. In addition, we would not mind if the waterfall was a bit quieter, since it is quite loud with the amount of water. I would really like to have a lower flow rate. This pump seems to large for this size pond, and I feel if I can lower its intake,
many of my problems would be resolved.
I do not want to spend the money on getting a smaller pump, which has a smaller rate flow. Is there anything I can do to my existing system/pump to decrease the flow rate? Is there anything such as a valve which can in installed somewhere which would regulate the flow rate and not cause any harm to the existing pump and system?