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-
(CAUTION: BE of these pumps-
by britta
1:31 pm in Seeking Advice by britta
This is from Jackson’s blog at Superforest.
I found my way into the vertical garden/hydroponics section of youtube, and there I feasted like a wild wildebeast.
I gorged on gallons per minute tables, pvc piping comparisons, and silicone sealant. I learned about pump volume ratios and outflow units and bleeder valves and plastic tubing.
And in the end I thought: I could design a system for growing food and flowers just like these but much, much simpler.
And so I went to the drawing board and tried out some ideas…
And here we are now.
My idea, which I happily share with you all, is to use a six-gallon bucket, a few lengths of pvc, an air pump, a short section of tubing, some zip ties, and one-gallon milk containers to create a personal, scalable, hydroponic (soil-free) drip-irrigation food machine.
I call it: The Jackpot.

An air lift is a wonderful and simple device. It’s just a length of pipe, open at both ends. You feed an air line into the bottom of the pipe and submerge it under water. The air bubbles within the pipe form an upward current and water is carried up to the top of the pipe. Simple, cheap, effective. Here’s a viddy to help explain.
The problem with a single air lift is they can only lift water a short height. Conceivably, combining multiple air lifts within a larger pipe would allow one to lift any amount of water to any height required, provided you had sufficient air flow. This idea probably originated in ancient Persia, I’m not making any claims to it.

So, a hanging garden set up, where water is pumped to the top and there trickles down through multiple growing containers before eventually feeding back into the main reservoir, all built around a central multiple air lift is the problem that’s been bugging me for the past few weeks.

P.S. I awoke from a fever dream and drew this schematic! Cool, no?

Tags: air pump, airlift, airpump, pump, pumps