Colleen,
I am still designing and planning the construction of my outdoor fish tank and I really would like to have it operational 24/7/365 here in Nebraska where our USDA cold hardiness zone is 5a and our heat zone is 7.
I am not sure I understand the zone ratings they have assigned to our locale.
The description of zone 5a for cold hardiness is that the average annual minimum temperature is -15 to -20 degrees F (and we border on 5b which should be -20 to -35 degrees F).
In my lifetime, I have rarely observed the temperature here to fall below -15 F, therefore I don't comprehend the "average annual minimum" being -15 to -20 degrees F. I think my area should be more towards the 6b zone. This zone covers the 0 to -5 degree F range. That minimum temperature range I can buy.
Regardless of the cold hardiness zone assignment, that still means that it is below the freezing point of water for many days and nights during the winter season.
I use the guideline of winterizing my cabin water system, i.e. taking my pump and well out of service at the cabin, on or before October 15th and I don't set it back up until April 15th.
This assures me that I never have any frozen pipes or broken pumps. Since I do not stay at the cabin during the winter months I do not heat the place, so I cannot leave the water works going for the obvious reasons.
In the future, I plan to change this and heat the cabin and have water available all year around.
This presents another dilemna as I cannot install my outdoor fish tank, filter barrels and pipes below grade (underground) where they would have insulation from the cold temps.
My cabin lot is adjacent to the river and we do get flooding, so I will have to elevate my pond tank and barrels sufficiently to prevent them from filling with flood water and silt or even floating away or otherwise damaged.
Basically what this all leads to is that I need to insulate and heat everything above ground if I want to keep it fully operational all year long. I have access to a lot of really good insulation materials at cheap prices, but I need to discover the best method to keep the water heated to prevent the water from freezing in the pipes running from the pond to the filter system and back to the tank. I would also like to keep the temperature of the bio-converter tank above 45 to 50 degrees F at least. This way, the nitrifying bacteria will only go dormant or slow down their metabolism, but not be killed off.
I do not think a simple tank heater like you would use to keep a small hole open in the pond ice would be sufficient. i am not sure what I will need as I have never attempted this before. I have some ideas for a heating system, but not sure how well they will operate.
My current idea is to use an "on-demand" or "point of use" water heater and either run the pond water directly through it (the most efficient heating method) or install a heat exchanger of some sort (maybe coils of copper tubing) and run an antifreeze solution through the coils to heat the water in one of the barrels or in the actual pond/tank by conduction method.
Another idea I have is to utilize a solar panel to heat the circulating water during the daylight hours and the electric "point of use" water heater at night. That would save some money on energy costs. The pumps are going to have to run 24/7 during the cold winter. However, I wouldn't have to run a heater 24/7 because the temps may not always be that cold. As long as the solar panel was supplied with running water, it should not freeze in the night and during the day, it may gather enough energy from the sun to keep the pond and filter tanks and pipes warm enough to not freeze overnight. If the temp drops too much overnight, the "on-demand" water heater could kick in and maintain the temp until the sun comes back up.
Do you or does anyone else wish to offer any suggestions for me on this subject?
Colleen, you seemed to be the most likely person to ask since you are about as far north as anyone else on this forum so you deal with the cold (and colder) temps more than most of us do down here in the more temperate areas of the US. Obviously, the title of your thread brought me here to ask questions.
Gordy
