http://texasfishingforum.com/forums/ubbthreads.php/topics/6252111/1

Here is a link to the thread Jackson was referring to. I added the filtration system just like this to a bait well on my boat and it works great. The bait lasts longer than I do in 100 degree heat...provided I periodically add ice to it because mine is not insulated. However thats a trade off I dont mind for not losing any fishing space. Certainly not as good as a manufactured bait tank, but this addresses the original post.

frozen water bottles like mentioned earlier and rocksalt

I made this out of at 15 gal drum. I have kept shad alive for a couple of days with it.

http://youtu.be/3l_3Yiftjx4?hd=1

birddogcatfish you don't want a timer the pump, filter, aireation system needs to run ALL the time. Keeping bait alive is hard but just as important and much harder is keeping them in good shape. Fresh, healthy, frisky shad will load the boat when live shad won't get a bite. Even with the best kept shad the difference between six hour old shad and fresh shad can be completely adamazing in how they catch fish. Keeping bait alive is only half the battle.

Cool , I appreciate it

I've made many. Here are some of my early ones. They turn out really slick now days. Good luck. The greyline tanks are the way to go if you have the money to spend.