Lighting 101 Help

[swampdonkey]

If you have a 32 watt light fixture that holds 2 4' bulbs, how many 20 watt light fixtures that hold 2 2' bulbs would it take to put out the same amount of light? I'm debating where to use the 4' light, which will hang over the tank's side, or stagger two 2' lights within the tank.

Appreciate any feedback!

 

[cp-connection]

More info! Assuming we're talking florescent bulbs: look at the print on the bulb. What is the wattage? And is it a t12, t8, t5?

edit: I'm not very familiar with t8, but that's probably what you have if you have a fixture that holds 2 32watt/4' bulbs. It looks like one 4' bulb is about 2700 lumen when its new and in an electronic ballast. My assumption has always been that 2 foot bulbs are half the lumen of a 4' bulb, but I could be wrong!

 

[swampdonkey]

Yes, florescent fixtures, t12's...have not obtained the bulbs yet.

 

[Av8tor1]

4' 32w would be T8's I believe

 

[swords]

You have a 3 ft tank I take it?

It would take Four 2 ft 20 Watt/T12 bulbs to equal the 80 watts put out by Two 4ft 40 Watt/T12s.

I don't know if the lumens match up however so you'd have to compare packages at the shop.

The twin tube 4 ft shop light is the cheaper bargain since fixtures run about $8-20 and the bulbs are standard size. The two footers are far more expensive for both fixtures and non standard size bulbs.

Home Depot used to even have a 3 ft fixture & some bulbs (but not all bulb types) but that was even more expensive than the 2 ft. I don't know if they still have these or not.

 

[rattler]

far easier and cheaper in the long run to just work with 4 foot shelves or as near to it as possible(i use 44 inch wire racks....close enough)....your collections going to grow and your going to use the space soon enough.....just do yourself a favor and run 4 footers.....

short of special display terrariums i wouldnt use anything else

 

[swampdonkey]

Yes, you are correct...they are t8's.

 

[swords]

T8/T12 it doesn't make much difference to my answer. 4 ft is the more cost effective choice.

 

[Rocketcaver]

I aggree with rattler 100%!
You will need the space eventually so why limit yourself?
Plan for the future, you'll be glad you did.

 

[swampdonkey]

Sounds good. I'll run w/ the 4'. Thanks for the quick replies!

Lastly, are the two bulb fixtures usually satisfactory or better to go w/ the four bulb in terms of output?

 

[swords]

If you can get a 4 foot fixture that holds 4 tubes (160 watts) go for it, more light is ALWAYS better!

I have two cheapie 4 ft fixtures (4 tubes/160 watts) over each of my grow shelves on my rack, the plants would probably like six tubes/240 watts over each shelf but I may want to erect a second 3 shelf rack and not blow the power in my house! lol

 

[rattler]

i run a minimum of 4 tubes/4 foot section.....prefer 6 if i can make it work.....

 

[swampdonkey]

The 4' four tube setup is what I'll use. Again, thanks all for the comments.