Planted Tank VIP
Join Date: Jul 2002
Location: Winston-Salem, NC
There has been a misconception running around that you can take a big ballast and run a small bulb and have the big ballast overdrive the small bulb. This is not so. When I measure current versus a smaller ballast or standard ballast, it is essentially the same. So I did some research and found that most electronic ballasts are load sensing and will limit current based on which bulb is connected to the ballast. Running two bulbs in series at least tricks the ballast into thinking it is a larger bulb, but the two 24" bulbs won't be any brighter than a single 48" bulb or even two 24" bulbs, wired independently, on a standard ballast.
You need to hook up both leads. Now the ballast will be overdriving 2x. Light output won't double, but come close to it. I'd say for 2x, light increases by 70%-80% (rather than 100%).
All you're doing by purchasing a larger ballast is increasing the current capacity, but you won't necessarily deliver increased current unless you trick the ballast and connect both leads.
- Sam P -
plantedtanker in limbo - all tanks currently in storage