Stacking AP cages

So I just purchased two T8s and I was planning to stack them. However, I keep seeing stuff about needing air flow on the UTH. Do I need to leave space between the top of one cage and the bottom of another? Or can I just leave it flush with both?

If I need to leave space, any suggestions as to how?

Thanks for any help/advice!

It is recommended to leave a gap between the UTH and the bottom.

I used furniture felt pads to raise the T8 a bit. That will give you just the clearance you need for the UTH.

Sent from my SAMSUNG-SM-G920A using Tapatalk

In reality you don't need that much of a gap. As always though, I have to recommend not using a UTH and just using a radiant heat panel if you have the funds to do so