Light Tubes

[shell]

I have a 33 gallon long and am using 2, 25watt aqua glo lights.  I bought a 25 watt cool white bulb at Rona last night, only to bring it home and discover that it was about 6 inches too long and way too thin to fit in my canopy.  I want to try the daylight delux tubes but cant seem to find the right size to fit.  I thought the size of the tube also went by the wattage, that all 25 watt tubes would be the same size.  I guess my only course of action would be to measure the part of the canopy where the tube would fit in and measure the light tubes at Rona.  Any suggestions?

[darkdep]

The wattage is USUALLY a good indicator but isn't the best way to go. 

Your tank is either 30" or 36" long.  That's a hard size to get decent bulbs for from HD/Rona (I know, I tried). 

Measure the area where the light bulb would fit, yes.  It won't be exactly a number that you expect (i.e the 36" measurement for bulbs includes the endcaps; so you may find a bulb is 35" or something like that.  But when shopping it's always a "normal" multiple like 30, 36, etc)

Measure the thickness too.  Sounds to me like your old bulb is a T12 light (1.5" wide) and you may have purchased a T8 bulb (1" across).

[BigDaddy]

I'm pretty sure the only 25 watt bulbs are T8F25 bulbs and T12F25, both of which are 36 inch tubes

T8 refers to the thickness in eighths of an inch (so 1 inch on a T8) and F25 stands for Fluorescent 25 Watts

Standard T8F25's are 36 inches in length.

That being said, most 3 foot tanks come with a hood that only houses 24 or 30 inch tubes (mostly 24 inchers).

Follow DarkDep's advice and take some measurements.  Better yet, bring one of your bulbs to Rona/HD and have a sales rep get you a replacement.

[darkdep]

However;  If your tube turns out to be 30", you're not likely to get a suitable replacement at HD/Rona.  They don't carry much in that size, and if they do it's only a cool white (which you probably don't want, because they don't look very good over a tank).  You may be forced to buy a more expensive tube at a place like Big Als.

I've never had so much trouble with finding suitable bulbs than I did with my 30.