What size pump?

[SirSmksAlot]

Hey guys, I am in the process of building a rdwc system. I'm running 4, 5 gallon buckets with a 5 gallon resivior. I'm using 3/4" drain line with 3/8" feed line. The guy at my hydro shop recommended a 395 gallon per hour pump. I'm just wondering if this would be to big of a pump? I'm worried that the drain won't be able to keep up with my feed. I don't want to cheap out and under power it either. My other option is a 195 gallon per hour pump. Any advice would be appreciated.

[Toker1]

Go with the larger pump. If you really are concerned about proper in feed to the pump, slightly raise the plant buckets to a higher level than the reservoir. This will utilize gravity to help with that extra suction. The higher you raise the buckets above the reservoir, the more head you will gain to feed your pump. Adjust accordingly.

[Tazard]

Great answer! You can also google pipe flow for ___diameter and you will see with small changes in pressure the flow almost does not change within a given diameter So you can add up the flow from your three eights inch lines and figure it into your three-quarter inch line just assuming zero pressure.

By the way I run a recirculating DWC with a remote chiller. I pump the water from the DWC to the remote chiller and gravity flow back to the DWC. I have the opposite situation I want to make sure that my pump is stronger than my gravity return. I can slow the feed to the DWC by raising the return line above the waterline in the DWC thus decreasing the head between the remote chiller reservoir and the DWC.

[Budler]

I was searching for some water pumps the other day. You can buy one with a controller. You can adjust the running speed. Check the pictures.
I wouldn’t go cheap, when a pump has to push the water up, it really decreases on the performance. So rather buy a higher volume one and adjust it for your needs.

[SirSmksAlot]

Thanks for the info guys.