Aquaponics sumps, wash bays and the third career

A container that will be cut, plumbed, painted or buried gains nothing from cosmetic condition. Buying grade A stock for a build is money spent on a wash cycle nobody needed, and it takes a good container away from somebody who wanted to refill it.

Eight things people actually build

1. 01Rainwater harvesting arrays — two to six totes manifolded at the outlet with a first-flush diverter and screened inlet. Far and away the most common.
2. 02Aquaponics and hydroponics sumps — cut-top grow beds paired with a full tote as a sump, bulkhead-fitted for pump and return.
3. 03Jobsite wash bays — a tote on a welded stand with a spray wand, sediment trap and greywater capture, which keeps runoff on site.
4. 04Dust suppression skids — tote, pump, hose reel and spray bar on a forkable steel skid. Standard kit on demolition and aggregate sites.
5. 05Brine and de-icer stations — insulated or heat-traced units with a metered draw-off for municipal winter operations.
6. 06Planter walls and green screens — halved bottles in reclaimed cages, drilled and lined, stacked into modular planting.
7. 07Storage stillages — cage and pallet with the bottle removed and a hinged door added. A forkable stillage for a fraction of a new one.
8. 08Compost tea and liquid feed brewers — aerated tote with a recirculating pump, diffuser ring and drain manifold.

The four variables

Pressure, and the sprinkler disappointment

Gravity gives about 0.43 psi per foot of elevation from the water surface to the outlet. A tote on a four-foot stand therefore delivers around 1.7 psi when full and less as it empties.

That runs drip irrigation, a soaker hose and a watering can. It will not run a sprinkler head, a pressure washer or a hose-end sprayer. Raising the tank is not the answer — reaching 20 psi by elevation alone needs a stand about forty-six feet tall holding a ton of water, which is a structure rather than a stand. Use a pump.

Where food grade is not optional

If the water touches something people or livestock will consume, the container history matters as much as the water. Irrigation water contacts produce. Livestock drinking water is drinking water.

Use documented food-grade stock for those, and check local rules — some jurisdictions regulate rainwater harvesting and a few restrict it outright.

Built or kit

We fabricate finished assemblies in the cage shop and we sell the fittings loose. Roughly half our fabrication work starts as a paragraph and a phone photograph, which is a perfectly good way to specify a build.

Cutting and fabricating safely

HDPE is pleasant to work and has two hazards people underestimate.

1. 01A raw cut edge is genuinely sharp. Deburr everything you cut, immediately, before somebody runs a hand along it.
2. 02Cutting produces fine plastic swarf that gets everywhere and is a slip hazard on a shop floor. Sweep as you go.
3. 03Never cut a container that has not been cleaned. Residue in the wall becomes airborne with the swarf.
4. 04Do not use a torch or hot knife on a container of unknown history. Heating unidentified residue is a bad idea in a way that is difficult to predict.
5. 05Support the wall when cutting. Unsupported HDPE flexes and grabs the blade.

A jigsaw with a fine wood blade is the right tool. A hole saw works for bulkhead fittings. Both offcuts and swarf are recyclable — bring them back rather than binning them.

Bulkhead fittings, which is where builds leak

Almost every leak in a fabricated tote build is at a bulkhead fitting, and almost every one of those is the same three mistakes: a hole cut oversize, a gasket on the wrong side, or the nut tightened against an unsupported flexing wall.

Cut the hole to the fitting's specified size rather than to what your hole saw happens to be, put the gasket on the wet side, and back the area with a stiffener if the wall flexes when you press it.

Choosing the right container for each build

What we will and will not fabricate

We will build almost anything from a container that does not involve pressurising it or using it for something its history disqualifies it from. We will not fabricate a potable water system from industrial stock, and we will not modify a UN-rated container in a way that invalidates its design type without saying so in writing.

Everything else is a conversation, and it usually starts with a paragraph and a phone photograph.

Questions about builds

Can I stack cut containers? No. Cutting the top removes most of the hoop strength, and a cut container is a vessel rather than a structural element. Support it on a stand, never on another container.

Will a tote support itself when full of soil? For a planter, yes, at modest depths. Soil behaves differently from water — it does not equalise pressure the same way, and the cage takes the load. Keep depths sensible and support the base.

Can I paint the bottle? Yes, with a paint formulated for polyethylene, which is a short list because HDPE is deliberately hard to bond to. Wrapping is usually easier and works better than painting.

What about UV over ten years? A natural bottle in full sun will embrittle at the surface within a few years. Wrapped, shaded or black, the same container will outlast the project.