Internal vs External Ballasts for lighting systems

[lost_at_sea]

Hey all,

Wondering if anyone can shed some light onto the main differences between internal and external ballasts when looking at lighting systems?

The things that come to mind initially are weight of hanging the fixture and the extra heat the internal ballast would give off near the tank surface as opposed to the external ballast.

Anyone have anymore insight into which would be preferable??? 

Thanks!!!

[mikerobart]

I think you've hit the nail on the head, weight and head are the main issues. That being said, if the fixture is far enough off the water, heat shouldn't be too much of a problem, just keep it well ventilated, external fan if necessary but often not.

I recently purchased a really awesome fixture from a member here. It is the type with the internal ballasts ( 2 x 250w hqi, and 2x24w pc), and yes, it is on the heavy side, but still will not be a problem to mount it, either from ceiling (same way you would have a ceiling light essentially.. be sure to hit 2x's, not just ceiling)  or, in my case, in an apartment with a landlord who might not like that, I will probably follow tskinner's design of a electrical conduit type diy hanger - looks sharp and will support the weight if done properly. My fixture is a bit of a brute, probably 35 +lb, but it's solid as a rock and  means not having to squeeze bulky ballasts behind my stand or under my stand, it will be packed enough already in there!

[mikerobart]

I should have asked, are you talking about halide ballasts or t5ho ballasts? The t5 ones are MUCH lighter usually. Something like the sunlight supply tek light, even the 48" 8 bulb, is probably only 10 lb or so, hardly heavier than a ceiling plant / pot. It seems most t5 fixtures have internal ballasts, with most halide fixtures these days being external.

[JD]

I am using two different 6 foot fixtures over two different tanks. One has no ballasts and the other has only ballasts for the T5's. Both fixtures have single ended halides, T5's etc. Given the choice to do it again, I would like all the ballasts to be remotely mounted. The fixture will be easier to handle, mount, and will be lighter, cooler and will probably last longer. Heat is the enemy of all lighting and electronics. And if you have the same luck as me, you will appreciate no electronics in your hood when you drop it into your aquarium water!
If you are using halides consider double ended(HQI) and Lumenbrite reflectors. You get the more usable light, can use lower wattage bulbs saving hydro, and will add less heat to your water. I wish I had gone this way...next time.
Patrick at Ottawa Inverts uses these. They seem to work well.

[lost_at_sea]

hey thanks for the replies... Yes I was primarily referring to MH ballasts, more specifically i've been eyeing this fixture on aquariumpros: (http://www.aquariumpros.ca/pp-classifieds/showproduct.php?product=18356&cat=36)

Ideally I wanted one that was listed on here a few weeks ago with 2x250 + t5's for the same price.. but my brother beat me too it

I'm not in urgent need of lights, my tank is still a few months away from being ready so I may still wait to see if another fixture with an external ballast comes on the market.... that or use my key to my brothers house and go steal his fixture