Link: https://www.catchpower.com.au/

I've had one for 5 years now and it saves so much money. Feed in tarrifs suck, so just store everything excess in your hot water heater.

be cautious of stagnation.

The result is a high pressure, high temperature condition that can damage the system over time by subjecting it to extremes of expansion and contraction.

basically you'd need to add more water dumping the old. heat a huge area of water like a pool, or stop suppling heat to the water when it reaches temp.

The water heater's normal thermostat is still operational. If the max temperature is reached, it just open circuits and then the solar energy goes to the grid again.

was more mentioning this so others know since you've been running it for ~5 yrs.

used to sell solar radiant heaters for pools and whatnot, and it was crucial that people know they needed to dump the solar when the water hit temp to avoid all the toys breaking.