SSPA Water Cooler - Some Assembly Required

I have most of what I need for this area of the new amp now.  I still need to get a few 1/2" tee's.  I got some 3/8" tee's but they're way too small even for the 3/8" ID hose.  Not sure what they were measuring when they made those!    

So I'll have to make a trip to Lowe's or Menards this weekend.  I also want to try using Flex Seal in my 5-Gallon Reservoir.  The Tank is carbon steel, and isn't lined with anything that I can see.  I'm not going to risk it.  I already know if there's no coating on it, the first time I run water through it, there'll be rust.  And then it's almost too late to continue trying to use it.  So I'm going to try sealing it, and hope that Flex Seal can handle the intended use I have for it.  

These pictures aren't really showing anything in final assembly yet.  But may give some idea as to how this'll start to go together.