This gets way nerdy on the pump/plumbing of the Reservoir System. Beware. If you are super nerdy, this is where you can jump in and start making this system better!!

Your reservoir system is a liquid circuit controlled by a pump on a timer. The pump needs to only pump water, not air. Running a water pump dry will kill it. The relationship between the amount of time your pump is turned on by the timer and the gallons per minute flow of your pump dictates a minimum amount of water in your system and, therefore, a minimum size for a sewer pipe reservoir.

However, there is plenty to tinker with here.

Here are notes from my thinking when I wrote that part of the Reservoir system How-to. They are notes that I have not really edited, so ask questions if something is unclear,

Theoretically, let’s say our pump pumps 500gph. That’s about 8.3 gallons per minute. We have decided that we lose about 25% to the curve at the top of the reservoir, and we probably lose about 10% to any remainder at the bottom that is too low for the pump intake. That means that when the bottom reservoir is as full as it can be, only 65% of the water in the tube can actually cycle through the system. So, 65% has to be at least = 8.3 gallons, which means the total pipe capacity if completely full has to be 12.8 gallons.

The pipe formula is

length of pipe = volume in gallons/0.00432900433 x Pi x radiussquared

so when the radius is 4” for the sewer pipe with 1/8” thick walls, the minimum pipe length formula is

GPM/0.21759949= min pipe length

For this 500 GPH pump, minimum pipe length for a one-minute pump-on cycle with the timer we have recommended is

8.3/(0.00432900433 x 3.14159265 x 16)=

8.3/0.21759949

= 38.14”

and if you want it to rest inside the window sill, that has to have the pump length added to it, which puts us at more like 40”

A typical window is 36” wide. So:

1- Maybe we don’t need this fancy a pump because we are only pumping up about 4+- feet of head. Maybe we could find one that would fit inside the reservoir so we don’t have to suspend it outside.

2- If we still want to use this pump, we should have people make them wider than their windows and suspend them outside the windowframe.

3- ??

RESEARCH—

Ecoplus pumps correlated with head and cost are here: http://homeharvest.com/hydroponicpumpssubmersible.htm

(CAUTION: BE of these pumps-

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