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Re: Lighting for 90 gallon

(two 48" bulbs and two 24" bulbs).  I am still a bit confused as to the whole
T8/T12 thing.  I am not sure if both can be used in my lights.  The one light

T8's are 1" diameter, T12's are 1.5" diameter. The number is the diameter in eighths of an inch. T8's will generally give you more light for less wattage, last longer, cost less, etc... T8's are an all-around better light bulb to use.

You can normally run a T8 bulb in a T12 fixture. Worst case you overdrive the T8 a bit, which isn't really a problem -- it will just shorten the life of the tube a bit. Most fixtures that I have tried that can start a T12 bulb will not have a problem starting a T8 bulb. I don't know about the other direction since I haven't tried it too often, but I suspect you would have the best luck using instant-start ballasts if you want to be able to use either T8 or T12 bulbs interchangeably in the same fixture.

T8's in 48" lengths are the commercial lighting standard now (and have been for some years now). As a result they are made in massive quantities and will be the cheapest lights for your tank. There is a wide selection of bulbs out there. People have had good luck with the GE Chroma 50's and the SPX50's from (GE? Phillips? Can't remember for sure). Chances are either of those will probably work in your existing fixture. If it doesn't you'll need to swap out your ballast which is going to be about $20-40 depending on what kind you get. As long as your current fixture uses bi-pin (2 pins about 5/8" apart) you'll be OK -- T12's and T8's both use the same bi-pin sockets. The older 1-pin (big 1/4" diameter pin on each end of the bulb) is much less common. Chances are that even if you need to swap out your sockets, they will be standard snap-in type sockets that you can get at Home Depot for a few bucks.

with the 2 24" has T12s in it now the light made for 2 48" bulbs has no bulb
in it and I don't know which it is supposed to have.  If I am going to use
this for freshwater plants and fish which size bulb should I use (T8 or T12)
and which K (5,000K, 10,000K, etc.)?  Specific brands and names would be nice
to make shopping easier.  Keeping cost down would be nice too.  I do not
particular like the yelowish lights, but if they are good for the plants I
can probably mix them with whiter ones.

Anything over about 5000K-6500K is going to put you into the specialty aquarium bulbs which are FAR more expensive. The GE Chroma 50's can be had from Grainger for around $5 in low quantities (eaches) for a 5000K bulb last time I looked. If you're on a tight budget that will probably be your bulb. A lot of successful planted tanks live under lights like that. The lower color temperature flourescents usually look pinkish or greenish rather than yellowish. You may want to try using a few 5000K bulbs along with one or two 3000K-4000K bulbs (NOT the 4100K "cool white" bulbs though), something listed as a "daylight" with a low color temp. The mix may provide a blend of light that you'll find more appealing to the eye.



Waveform Technology
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