BACKGROUND: So I have finished mocking up my system. 2 IBC, 1 Sump 1 Fish Tank, 2 IBC growbeds and 4 cut barrel Grow-beds.. I ordered the Laguna 1350 water pump, just FYI you can get a free $30 Laguna Airpump currently when ordered with a 4 year warranty for $169, I thought it was a great deal considering warranty. I am using Blue Tilapia, claim that they can handle colder weather if needed down to 45F. I have found a quality breeder that is going to set me up. Luckily he is local so I am picking them up myself, gotta get a battery air pump, will be good for backup anyway. I plan on keeping indoor 2 regular 30 gallon heavy duty plastic tote tanks as fry holder (may only need one at first) and a 50 gallon aquarium for my 2 breeder sets to start off with. My original plan was to get a cycle of moving most of them outdoors when weather permits here on the North Carolina and Virginia border, and always leaving 2 breeding pairs indoors to allow them to replenish my stock when I harvest my outdoor aquaponics fish going into every winter. I have bought a 12x12 Rhino Greenhouse with 20 mil polyethylene to put my aquaponics system in. Electricity here is some of the cheapest there is, I feel for some of you that have 5-10x the electrical cost. I will be able to run a very efficient blowing space heater to maintain things from freezing in the winter with hopefully no real issue.

Do these submersible water heaters actually work (esp if you use a couple)? If so any recommendations?Any other simple water heating options for a fully covered 20 mil greenhouse in winter in Virginia/Carolina? Having control over water and air temp I feel will give me the greatest odds in Winter. I would like to keep the fish in the system year round to grow winter able crops, and will probably keep some goldies in there due to hardiness as well. If I convert my indoor breeding and fry sets from typical aquarium setups to a small indoor aquaponic setup, are there any recommendations on cheaper light systems?

Thanks for all the help, I will be sure to unveil the final system when completed, and hopefully in time will be able to give quality information to others since so many have helped me.