Cecil, how long do you thing those tanks will hold up if outside in the sun?
Thinking for the future, and thinking about ways to hold smaller quantities of fish here before delivery or for customer pick-up.
No filtration, I'd use a flow thru system using pond water. I'd have to also figure out a bottom drain flush system to clean the poo out of the tanks daily.
I honestly don't know about outside longevity but you could ask the company. I did have one outside in the shade for one summer with no issues. Now I use an 8 foot blue plastic stock tank for outside as I needed a larger tank. I've had that one for four years now with no issues. Even store it outside upside down for the winter. (Won't fit through a doorway).
As far as a bottom flush system you can't go wrong with a 3 inch unseal, short section of 3 inch PVC pushed through it with a shower drain glued in. If you glue an end cap on to a section of PVC and then cut most of it off you will have a lip to keep the shower drain from pulling through the Uniseal.
Then an elbow and 3 inch pipe parallel to the floor or ground, culminating to a knife gate valve and an external stand pipe. On the other side of stand pipe (T with vertical pipe fitted in) is a barb fitting and a water line to direct waste water flow. Awesome stuff for a garden or your lawn!
Pull the knife gate valve and the water around the drain in the fish tank rushes to the top of the stand pipe with enough force to really suck out any solids in the drain and around it. Amazing how dark it is if the fish are tilapia!
I use fernco couplers to put sections of it together to make disassembly easier. You can set the whole thing on one or two rows of blocks to get the blue tanks even with the fish tank. You can use less blocks if you have piece of plywood under the tank between the blocks.
Remember how many blocks it took at the Aquaculture convention in Shipshewanna? Don't do that anymore! Crazy times!
Edit: Just realized you said flow through. In that case just dig a trench under your tank to fit the bottom drain and you are good to go. 
