I'm putting together a greenhouse that will have 2 X 1000L water tanks (IBC tanks). I've painted them black to absorb heat from the sun during the day. The goal is a 4-season greenhouse that won't freeze in winter.
However, in the winter, I am concerned that the tanks might freeze over. The greenhouse area is 10' X 13' and its height is 8'. The walls are polycarbonate (6mm thick), and assume that it is completely sealed without air-gaps.
The goal is to minimize electricity usage. Aquarium heaters unfortunately heat to 20C at minimum so this would be inefficient. I only need to prevent freezing (but can't add salt as the water will be used for plant irrigation).
Given my latitude of 43°N (Niagara region), will I need active heating, and what do you recommend (type and wattage)?
What I've looked at :
- aquarium heaters (submersible type)
- this type of heater : https://www.amazon.ca/gp/product/B000HHSI1E
Also, the 2 tanks are connected to each other on the bottom via hoses — will the hoses need to be insulated?
+++ Addendum : the tanks are INSIDE the greenhouse.
Appreciate any advice! Hopefully not an overly-expensive solution.
Thanks,
Gene
Best Answer
Another option; use low wattage aquarium thermostat/heater like 25 watt ( maybe more for your location , my coldest weather is only about +20 F). Only turn on power when a few days of freezing weather is expected. If the power is left on a few days extra, the low power usage will not be high. The hoses need to be insulated as they will be the first things to freeze. The main concern is the surface of the water will freeze and build up pressure; For pools an inflatable bladder ( such as a tire inner-tube ) is anchored at the surface. Then the surface cannot make a pressure tight barrier permitting a pressure build up in the water.