They do work great even with 100 degree water, make sure to use a pump that can handle the heat. Also in my original frescas, the powder coating between the glass started flaking off.
I'm not dissing on the frescas, I like them a lot. I just made a lot of mistakes with them, if I share them with you, it may make your road less bumpy.
I used RO water in one of them not knowing better. Tap water is better. I never used any glycol. I'm pretty sure that would have solved the powder coating issue. Once there is metal exposed. all of the different metals in your system are now connected through water and will start to interact with each other. I believe glycol will also reduce this interaction.
Test your no flow switch weekly, mine failed and I have heard of others failing as well. I used a high temp cut off as well. If my room went over 90 everthing heat producing is cut, as this indicates a failure.
Use a larger diameter drian line than your supply line, this will create negative pressure in the fixture. If you do develop a leak anywhere, air will leak in, instead of water leaking out. Do not use any type of vinyl hose, the heat will make it soft and it will collapse. I purchased a 50' roll of US made Goodyear reinforced rubber hose. I get it at harbor freight, it is 1/2" ID air compressor hose.
The rules of proper lighting still apply, if your running a 1k you still need to have 30+ inches between the light and canopy. You can reduce this distance alot more than an air cooled but you will fry your plants if you try to run it 6-12" off the canopy like it has been suggested in their advertising.