Can I use a 40w CF lamp on a 96w fixture?

[gu2high]

I have a Coralife 2x96w CF light fixture on a 58 gallon tank. If use both lamps I find it is too bright so I normally use one lamp only (i.e., 96w). By using one lamp, the other no-using lamp blocks the light to reflector and it has less useful light than one lamp only fixture. I feel the light is a little lower than what I wish. If I could replace one 96w lamp with a 40w (I know it is shorter), then it would be perfect. I just don't know whether it is safe to do it or the 40w lamp will be burned out quickly.

One thing I forgot to do it is, remove the no-using lamp and then it won't block any light to reflector and it won't be 'burned' by the other using lamp. I was stupid not to do it earlier.

 

[rkilling1]

Never thought of that before. IMO I would contact the maker of the fixture or even someone like Coralife and ask them.

I know people run 55 watt bulbs in a 65 watt fixture, but yours in quite a difference.

I'll see if I can find anything on the net.

EDIT:

The only thing I could find was there are maximum watts on the CF ballast's and no minimums. People have them configured in all sorts of ways.

 

[gu2high]

I opened the fixture, find two ballasts have lables on them: Coralife 120v 60Hz 1.35amp 81watts, Power factor:>=0.5, for 96w/PL Lamp.
I don't know if I can use 40w lamp on the ballast.

But, if I really want to do it, I can buy both a 40w lamp and its corresponding ballast to install in it. I measured the size of the Coralife ballast (8"x2"x1.25") so that when buying another one, I need make sure that it will be fit inside. May be I can go to a home department store to buy a cheap one.

 

[Lance M.]

55 watt bulbs "are" 65 watt bulbs if you get what I mean. Same goes for 28/32 watt compact flourescents.

"Bulbs are stamped "28W", but they will work fine in 32W fixtures. It's the ballast that drives the bulb, so if you have a 32W ballast, a 28W bulb will run at 32W and vice versa."

Straight from Hellolights.com. You even notice in their section with 65 watt bulbs, they sell them as 55/65 watt bulbs.

As to you question about a 40 watt bulb, I don't know it that will work but I dont think it will. I have a 54 gallon corner planted tank. The only fixture I can put on it is a 24'' one so I have a 130 watt (2x 65 watts) fixture on it.

 

[Zezmo]

The only way it would work safely is if the ballast was an electronic type that automatically "swichted" itself for the correct wattage. It would say "36/40/55/96" or some such on it. The nomenclature you indicated makes me pretty certain your ballast is only for 96w bulbs.

Why not just turn off/disconnect one of your 96w bulbs instead?

 

[gu2high]

Why not just turn off/disconnect one of your 96w bulbs instead?

There are two switches, each for each bulb, so I did turn off one bulbs. This is a no CO2 tank. If using both bulbs, it creates algae. If using one bulb, the light is a little lower than my wish to be.

 

[Purrbox]

You could create a physical barrier to block part of the light. Or perhaps replace one of the bulbs with a 50/50 bulb.

 

[gu2high]

"replace one of the bulbs with a 50/50 bulb" sounds like a good idea. I may try it in future.