I also keep my PFOs behind my tank (two dual 400 setups). I take the added precaution of putting them up on a couple of 2x4's to get max air circulation around them and to prevent directly sitting on the carpet. I don't think this is really necessary, but can't hurt since they do get fairly warm in operation.
Those suckers are pretty big huh? I have mine located in a closet right behind the tank on a piece of plywood. I like the idea of the 2x4 blocks though for the added circulation, hmmmm.....
My dual 400w pfo ballast is sitting on brackets on the side of the tank. The brackets are bolted onto the stand and we used to use these brackets for the kalk. drip. I'm using another kalk. drip so the brackets were taken off from under the tank and bolted onto the side. Mine also gets hot to the touch.
Our's is a Hamilton and it is very big also as is the VHO ballast from Hamilton.It gets pretty warm but not to ad at all.It is sitting on the floor under the stand.
Good Luck (that is a great lighting)
It's a bad idea to have it in your stand under your tank. Many people have trouble keeping their tank cool enough, and a very hot ballast under your tank will act as a nice heater, but I don't think that's what you want.
Our 120 Oceanic with 2-400 w/2-110 VHO has both ballast under the stand along with the refugium which has a 65w PC lighting it.The unit is a hamilton hood with two 4" fans inside the hood.The tank runs at 79' to 80'and we are in Texas(hit our first 100 'day today).I wish we could have put the ballast in a remote location, but being a display in a store we didnt have much choice.We bought a chiller when we set the tank up,but with it running as cool as it is there is no reason to hook it up.(not that we have the room under there with those huge ballast and 50 gal refugium)hehe
Just my 2 cents
Laterss reeferguy
I have a 6 month old son who will start moving around pretty soon so I think I will have no choice but to put it under the tank. The stand is 36" tall and 78" long, all return pumps will be in the basement so no additionall heat will be with it. What if I put a 6" oscilatting fan to blow the air around?
If it is PFO, you can buy extensions for it at www.premiumaquatics.com or www.marinedepot.com for about $15 per extension. I was lucky, my garage is directly behind my tank so I put my ballastsin the garage along with my chiller.
I have mine underneath the stand which is 72" in length and so far have no problems with it. In fact they are stacked up on top of each other using a red brick. They get a little hot and as long as the back of your stand is open then it should be OK. My only equipment that is outside the stand is the chiller and all pumps and calcium reactor and top off water are inside the stand. I like it this way cause it's neat looking. Although using a fan inside the stand like you said is also an option. Mine's been set up for 2 years now and also note that I'm using a chiller. HTH.