Light measurements

[Aquarius0015]

How does one properly measure the length of a fluorescent bulb? From the pins to the pins, from the metal caps, or just the glass?

I have a 16" hood for my 5.5 gallon. The light that came with it is 14 watts, but it gives off a weird purple color, almost like black light, lol. Since I have plants and I do not forsee my fish going to raves anytime soon, what length should I look for in a replacement bulb? Any suggestions as to brand names/styles/etc?

[adblair]

I have no idea how to measure, but why not just take your bulb with you to the store? :)

[Aquarius0015]

I'm clumsy and glass hurts when it cuts you. Never been to the hospital, nor do I want to go.

Edit: Really, it's just one less thing to worry about, and I kinda just want to know for knowing's sake. Learning stuff on AC forums makes me more confident when I walk into the LFS.

[Soulcoffr]

I think if you just measure the length of the tube and endcaps, you should be in the ballpark.

Fluorescent tubes come in set lengths, so if your tube is in the neighborhood of 18", then you'll probably need an 18" tube, because the next step up is 20". And step after that is 24". I think 24" is the longest "short" tube, the next step up is (correct me if I'm wrong) 36".

You'll also want to note the pin arragement and tube diameter as well. Some tubes have one pin on each end, others have two.

You can go here to get an idea of what you might need...

http://www.lighting.philips.com/nam/product_database/

Hope that helps!

[adblair]

I'm clumsy and glass hurts when it cuts you.

:laugh: :laugh: :laugh: You sound like my sister! Geez... I love her, but she is the only one I know who can fall out of folding chair (while SITTING) and break her arm! Maybe you better NOT try to take that bulb anywhere....:laugh: :laugh: :laugh: ;)

[Aquarius0015]

Good idea.

[Aquarius0015]

I went to a few LFS today to look for lights, but none of them carry fluor. lights as small as mine. So it looks like I will be ordering online and will not be able to do the handy 'bring the bulb with me trick' again.

I guess I'll start my search at Big Al's. Any suggestions as to brand or K (which I don't understand) or anything?

Edit: From endcap to endcap I measured just a little over 14".

[djlen]

Measure end to end, not including the pins and go to Home Depot or Lowes. They'll have plenty to chose from.
My suggestion......6700k 15 or 18watts.

Len

[Aquarius0015]

I just read the back of the hood. It says: "16" Fluorescent Aquarum Reflector, 120 volt, 40 watt 60hz." So even though the light it came with is only 14 watts, I could theoretically have up to 40 (not that I'd want to....)?

[Aquarius0015]

So really there is no need to buy one of those special plant-grow bulbs? Great news, I love saving money.

[Aquarius0015]

I looked all over the net for a 15" T8 6500-6700K fluorescent bulb. There is very little selection in this size, and all of them are 14 watts (which will yield about 2.55 wpg in my 5.5).

The only product that gives a value for K is a 8500K bulb. The description says,

"EMISSION SPECTRUM CLOSELY MATCHES ADSORPTION CURVE OF CHLOROPHYLL-A ,8500K HIGH INTENSITY LAMP WITH PEAKS EMISSIONS IN THE BLUE AND RED REGIONS TO MAXIMIZE THE PHOTO BIOLOGICAL PROCESS IN PLANTS. IDEAL FOR PLANTED AQUARIUMS AND TERRARIUMS."

All the other bulbs just say that they are good for plants, but do not mention *K.

This is the 8500K's link (Big Al's):
http://www.bigalsonline.com/catalog/product.xml?product_id=23607;category_id=1849

Which is a better decision- the mystery bulbs or the 8500K bulb? I did purchase an Energy Saver Color Max 14 watt bulb, but it gave off a similar purple color to the original bulb, so I'm going to return it.