Insulating above ground stock tank 7B

[A113]

150 gallon rubbermaid stock tank above ground in 6'x6' pvc raised garden bed with soil surrounding tank. Medaka rice fish (above 40°F required). 7B. Heater cost $$ over winter. Need suggestions for pond insulation. Thanks!

 

[GBBUDD]

I'd create an air space around the tank. Use rigid insulation 2 inch minimal leave a good 4 to 6 inch space all the way around they lightly stuff with hay. Do not compact . Cover the space with another 2 inch rigid so your just above the edges so in the dead of winter you can place another 2 inch across the top.of the whole tank glue it all together with caulking construction adhesive

 

[ADHDiy_Guy]

Question for you first, is the raised garden bed an indication that you are an avid gardener? Do you have a compost pile or compost bin? Have you ever considered composting your kitchen scraps?

Compost creates heat while it breaks down, even when it is freezing outside. In the winter you could make compost piles around your pond to build up the walls around it. This would both insulate and create some heat.

Not like… keep tropical fish warm, but for 7b that should be be fine.

 

[GBBUDD]

kitchen scraps

EQUALS RATS, RACOONS, BEARS,

 

[ADHDiy_Guy]

EQUALS RATS, RACOONS, BEARS,

I should say *results may vary due to your unique area and local wildlife.

I was thinking since OP said they were concerned with the cost of running a heater over the winter that the cost of rigid insulation boards might be a restricting factor as well.

One additional thought on the cost of a heater - since it is a 150 gallon stock tank (not a 2000 gallon pond) and you aren’t trying to keep the water temp at 72°+, you just need to keep the temp over 40°, you could buy a 100w aquarium heater for a 20-30 gallon aquarium, obviously way too small right? But if it’s set at a temp of 72°, it will still keep a warm pocket in your stock tank that is 5-10° warmer than it would have been without the heater.

Tetra makes small, fully submersible aquarium heaters in 50w, 100w, etc increments, and the 100w is usually $15-20 at petsmart. If your electrical costs are $0.15 per kWh, that would cost you about $10 or $11 per month in electrical costs to run the 100w heater. Thats not nothing, but it’s not terribly bad when you think about the wattage of your water pump or the wattage of some of the pond heaters rated for larger bodies of water.

 

[JRS]

Don't forget some kind of cover, which will trap heat and reduce evaporation. I used a couple large panes of salvaged tempered glass with a space left for air exchange to cover my 300 gallon turtle tub during cold spells to extend their time outside.