T5 Ballast advice?


I'm installing new T5's from ReefGeek and the ballast they come with is a very slim (low profile) Vossloh Schwabe ballast. I don't want to put the ballast in the canopy as it's not that large. I'm trying to decide where to best mount it.

One, I'm concerned about dissipating heat. The VS specs (as best I can find by searching on the web - I wish ReefGeek had sent it with specs/installation guidelines) say it should be a minimum of 4" from walls, etc. It also says it should be mounted to the fixture housing (which I assume is presumed to be metal for heat dissipation). If I were to mount it to the outside of the tank stand or inside under the tank, would it get to hot for the wood? And will it allow it to cool sufficiently? Or is a fan on it sufficient?

My other concern is safety. On the ballast it says it should be contained within an 'Electrical Enclosure' whatever that is. Doesn't seem like a bad idea to me since the wires are more exposed than my current ballast which uses plugs (this ballast has holes that each of the wires is inserted into). With water/salt in the vicinity, some sort of cover seems like a good idea, but that would defeat any ventilation options. Also, what type of casing would make sense and where does one find such materials?

That said, I love the light I'm getting now!


New member
I can help some, maybe. Most of the electronic T5 flourescent ballasts are pretty muich the same as far as recommendations of mounting. The housing is for two purposes, protect from exposure to the elements and protect from contact because it is an electrical device. Keep it away from pets, kids and possible exposure to splash or salt spray and you dont have to find an enclosure for it. THe mounting limitations due to heat issues can be mostly eliminated by using a fan to help cool the ballast. The recommendation for attaching it to the fixture is probably so the ballast case is grounded with everything else. The case should be internally grounded so mounting the case to the fixture would ground them together directly, assuming you mount the ballast to metal. The instructions are written for typical lighting applications where the ballasts are mounted with the fixture, typically. We cant always follow them, its a different application with aquarium lighting use. As long as we follow safe electrical wiring practices, it will be safe.

The ballasts dont get all that hot, they can get pretty warm but not smoking hot. I had both of mine mounted in a large, enclosed aluminum canopy with open ends and fans blowing through the canopy. Large fans, not computer fans. They just got barely warm to the touch.

Keep them away from potential moisture or salt spray and have a fan blow air on them, and keep out of reach of kids and pets. You will be fine. If you are worried about mounting directly to wood, put a piece of sheet of aluminum underneath them. This will shield from direct wood contact and also should help act as a heat-sink to dissipate any heat. The only thing I can think of is that there probably is a maximum mounting distance from ballast to bulbs. Probably need to stay within that.

I'm sure the lighting experts will jump in with more / better information. There are a couple here in the lighting / electrical field.