Inexpensive way to warm 150 gallons of water outside during the ten to five sunny hours? Featured

I'd have to wonder what flow rate city water pressure would produce through 3000 feet of hose pipe.

Sylvia.

The capacitive model only needs the capacity so flow rate is not important.

The pool solar water heaters work off of flow rate, where they usually raise the temperature a small amount on each cycle, with numerous cycles.

The capacitive solar water heater envisioned here is a reusable one shot. I guess you're bringing up the question of which is the best model.

The one shot can be filled from a garden hose spigot & emptied on demand. The flow rate models require endless cycles using a recirculative circuit.

They may have but many times I've left the drain hose in full sun the entire summer.

The smaller the diameter, the more surface area is available to heat the water, I would expect. Note that the channels on the fafco panel are something like 5/32", albeit water is being pushed through continuously.

The problem with PVC is that the UV degrades the impact resistance of the pipe. I.e., a minor impact may cause cracks or fractures.

You'll never get paint to adhere to thin walled plastic. Not to worry, the hose is dark blue. Close enough to black.

Be sure to let the OP Jim S know that his post has sprouted wings .. he seems to have forgotten about it. John T.

You'd be better off buying or making a solar pool heater type device. Similar devices were popular for domestic hot water before solar cells became cheap.

Essentially: A rectangular sheet of metal of a size to absorb enough sun energy, solder zigzag copper tubing to it so it can absorb heat from the sheet metal, paint it flat black, insulate the rear, a layer of glass in front to make a mini-greenhouse, install facing the sun, flow water through the tubing.

It matters when you want to get the hot water out.

Sylvia.