I have a rookie question here as I just started my Aquaponic set up. How cold can I expect the water to get in the panhandle, Milton FL 32571-1535. Tank sizes are 300 gal Rubbermaid on 4 inches of concrete. 275 gallon ibc tanks and does it matter if it is just one tank or 3 tanks hooked up together along with the 300 gallon sump tank?
If you look at last winters low temperatures in your area and average them, your system temp will tend to that number.
Water in a tank will lag behind air temperatures in movement but how closely the water gets to the air temp will depend on system design and any insulation. What sort of plant beds are you using? Simply knowing the fish tank volume only tells part of the story since NFT or Tower plant growing areas will heat exchange with air far quicker than a media bed and of course Raft beds are the most temperature stable. The more water volume in a system, the more stable the temperature will be but you can still expect the system water temperatures to get down to the average Temps over any given one to two week time span if you are not doing any heating.
In the panhandle though, the temperature will fall below safe tilapia temperatures likely no matter what you do unless you are actively heating the water. I definitely recommend sticking with native fish like channel catfish or bluegill that will handle the water temperatures and likely give you better growth in an unheated outdoor system.
Media beds half with hydroton and half with expanded shale. I am trying to order bluegills and catfish but it is hard to locate a supplier. I get we don't deliver or not in florida or just loads of question. Do you know anyone who is close up here or ships bluegills and or catfish. The prices on ebay are high for so few fish.
So How much grow bed do you have? Remember for your first season I would only recommend about 1 bluegill per cubic foot of media bed or 1 catfish per two cubic feet of media bed. I do not recommend stocking them together in the same tank since catching a bluegill from a tank with catfish in it would probably mean beating up all the catfish while trying to catch the bluegill.
As George says, Paul Fish Farms is in North FL so I would recommend contacting them and perhaps arranging to go pick up fish if you can. Down here in Central FL I get my fish from Florida Fish Farms.
Or if you find that neither farm will deal with your for a small quantity of fish, I have bluegill and channel catfish that I can sell in small quantities and breather bags to get them home in. Sorry I have to charge more per fish than they do but I can also supply mosquito fish. I don't ship the fish though so you would have to come down for a visit to my farm here in Yalaha, FL.