June 2024: Water.

With the solar system operational we , after another pause for farm related work, turned to setting up a reliable water supply and purification system. So we could wash produce, clean equipment, and, at last, wash our hands properly.

Reservoir type tanks are very expensive, and we had anticipated burning a lot of cash to obtain one. But Kenji saw a design on YouTube, and I recalled seeing a similar aquaponics tank made from heavy wire fencing and plastic sheeting. We decided to try it.

 First we made a five foot cylinder with the fencing and wired the ends together, making sure to keep the pointy ends pointed out away from where the liner would go.  

Wiring the ends of the fence together.

Our tank ended up five feet in diameter. That was just how much fencing we had available, so five feet. We used that to mark an area of ground and leveled it. It is very important that the ground is level! Too much slope and the tank will collapse. 


The post helped us measure how far to level out the ground. It is real important to level the ground, again. We used a level to make sure (not shown, but we did).

Flat shovels are good for leveling. This is me working.

Once leveled we put weedmat down. For padding against the wire we lined the fencing with 30# roofing felt. It is heavy and thick. We placed it horizontally, rolling the felt around the interior wall. A better way might be to cut it into vertical sections and overlap them, because the walls do stretch a bit when water pumped in. It is a LOT of weight, close to 5,000 lbs. of water for our tank. We found the felt tended to tear because of the way we placed it. Putting vertical overlap section might prevent that. Or not, we haven't tested it. Either way, fold the roofing felt edge over the top of the wire fencing. 


Kenji adding some soil to soften the bottom edge. Not sure if it helped, but it didn't hurt.

for the liner itself we bought a pond liner. It is a 20 mil thick 15' x20' tarp, basically, so we had to pleat it around the wall of the tank, folding it about every foot or so. It was $80 and the most expensive part of the tank. You can use  a 6 mil sheet of polyethylene doubled for about half the price, but it will not be as strong or as resilient or as UV resistant as a good quality pond liner. It is made from the same material as greenhouse plastic, LLDPE (linear low density polyethylene, if anyone asks).

The pond liner is basically a 15 x 20 foot, heavy duty LLDPE UV resistant plastic tarp.


Fitting the pond liner.

Kenji folding the liner into pleats to fit the cylinder shape of the tank.



The finished tank. You can see the aerator and red pallet where the pump and pressure tank will go on the left. The aerator is for making compost tea.

The tank filled with about 580 gallons of water. The wire fencing has a lot of tensile strength.

 We added a rope around the top later to neaten up the plastic liner (not necessary, but it does look nicer).
It is not pretty, but it works. Along with the wire (about $20 worth) and the 30# roofing felt (maybe $35), the total expense was about $150 or so, your results may, of course, vary. Compared to spending over $1500 for a similar capacity commercial tank, not bad. In any case it gave us the reservoir we needed to run a pump.  We missed on pointy bit and had a tiny leak, which we fixed with pond liner repair tape. No more leaks. We will also add a cover to retard algae growth.

Next: The pump subsystem for wash station and irrigation.


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