there are at least 4 ways to liquid cool your lights. I use a
hydrocoil- the company went out of business a few years ago, but there are few places that still sell the coils. About $200 will get you a coil that will cool a 600 watt bulb, which is what I'm using to grow.
The main drawback to this type of cooling device is that it is somewhat fragile.
I use a simple wing reflector and about 10 gallons of water that is cooled using a 20 foot copper coil with a fan blowing over it- keeps the water about room temp. Totally self engineered, but it works great- you can also buy something called an ice probe that will cool your reservoir using a thing called and ice probe
http://www.aquariumguys.com/iceprobe.html I am thinking about trying this out, but based on a 50 watt peltier plate, I'm guessing it would do the trick- or you could buy a bigger peltier plate and rig that up for yourself. Or you could buy a big peltier plate, a cpu cooling block, and a CPU cooling fan, mount the cold side to the cpu block and the hot side to the fan, then use a pump to cycle your water through the cpu block. This was something I mad scientisted when I was blazed one day, but I bet it would work. total cost would be around $100.
This is my first post here, but if I can figure out how to post pics, if you're interested, I can show you my setup.
100 gals a day? really? -rep to you.