The tadpole system is a five foot rack with a 40 gallon reservoir on top. This reservoir fills automatically with the regular carbon-filtered tap water that supplies the whole basement. There's a heater and a pump in the tank to heat and move the water around. There's an overflow in case the float valve ever fails. And finally there's a ball valve that drains the water into the tadpole tanks. Each tadpole tank holds 50 tadpoles. The tad containers keep in the smallest tadpoles and their food (as long as you don't use fine powders) but allow free water flow with the rest of the tank. I put a small water pump inside each tank to move water around under the false bottom. There's also a power filter hanging on the end of each tank to provide biological filtration. I have four tanks on the first row operational now (200 tadpoles!), and I have the tanks ready for a second row (and a third could be installed if needed). So soon I'll have 400 tadpoles in five feet of space! Every tadpole tank overflows to the floor drain. With this system I can feed the tadpoles like crazy and change the water on the tadpoles every single day with no effort (some days I change it more than once!). I feed them frozen brine shrimp, frozen mysis shrimp, algae, and various dry fish foods. My tadpoles morph out in about two months and they are very large and robust.
You might be wondering how I keep track of all the tadpoles in this system. Well, let's say I have 4 breeding pairs of leucs and 4 breeding pairs of azureus. Tads of breeding pair #1 go into tank 1. So there's both leucs and azureus in there, but they all come from Pair 1. All tads from Pair 2 frogs go into Tank 2, etc.. Then they all go into walk-out tanks the same way. This keeps the lineages straight but requires no labeling. If you only have one pair of each kind of frog, just assign certain species to certain tanks. Make sure the species going into each tank look nothing alike. For example green auratus goes into Tank 3 and bronze auratus goes in to Tank 4.
Building your own tad system!
The tad containers are tenite butyrate tubes from USplastic.com, item #42133. The tubes come in 6 foot lenghts and you cut them into 4" lengths with a table saw. The orange end caps are item #42107 from the same place. Use a drill press to cut out the center of the end caps. Then cut some fiberglass screen to be a little larger than the end of the tube. Hold the screen over the end of the tube with one hand and slide the end cap over the top of it to hold it in place. You're done! The screen can be found at any home improvement store and should be fine enough not to allow food pellets or tadpoles to go through it, but coarse enough to allow water to flow freely into the tube. Your tank will hold 50-55 of these tubes.
The footprint of each tank is 12.5" x 24". They are 6" tall. I bought them from glasscages.com. They are called 1/2 15s (half fifteens). Drill a 1.5" hole in the end of the tank for an overflow. I get the glass drill bits from ameriglas.com. They are about $40. Then use a 3/4" bulkhead fitting from drsfostersmith.com, along with a small piece of 3/4" pvc tubing and a 3/4" pvc elbow to finish the overflow. While you're at the home improvement store buying pvc pieces, get some eggcrate for light fixtures and make a false bottom (that white grid you see on the bottom of the tank). I use short lengths of pvc pipe as legs to hold up the false bottom. Then buy a little water pump, a power filter, and an aquarium heater at drsfostersmith.com.
You can set these up in several ways. The deluxe version is with a gravity feed reservoir above the tanks and all of them overflowing to a floor drain, as shown above. If you can't do that, you can very simply hang the overflow over a sink, or have it lead to a sink, or into a bucket. Then just pour water from a bucket into the tank (or pump water up from a big trash can or something). When the tadpoles sprout front legs just pour them into a walk-out tank. I've had these tanks up and running since early 2006 and they are working perfectly for me. I'm so excited to be done with manual water changes I just can't stand it!! These ended up costing me about $125 per tank. To pay for mine, I made 16 of them and sold 8 of them for $250 each. It was a "I'll buy if you fly" kind of deal! I haven't made anymore since then due to lack of time.