mind boggled but i want to take the lighting plunge

So that's two T5's, one full spectrum, one 6700k?

I think 30" T5s are 18w, so that'd be 36 watts or 1.8 wpg. The high end of low or the low end of moderate.

Lux is a measure of how light looks to us: doesn't have anything to do with how plants use it. Some bulbs for instance have peaks in the Red and/or Blue ends of the spectrum, less in the green. They might have a high lux (look bright) but not do so much for plants.

Watts are how much power is driving the bulb. That's what determines the brightness to a certain extent. Its a proxy measure, but its what most folks use. Compact Fluorescent is a bit more efficient than Normal Output, but the big difference is the size of the bulb: an 18" CF is 36w, the 30" T5 is only half that.

Kelvin (K) is a temperature scale thats used to describe the color of the light. 6700K is great for plants. Full-spectrum could mean anything.

This is the best I can come up with


K = color
lumens = light output
watts = amount of energy used

Most sites say K and watts are most important, not lumens.

K should be 6700

Watts-this depends on what kind of plants you are growing, co2, and how much work you want to put into it. Most people say 1.5-3 watts per gallon.

Look on the actual bulb, by the pins, for the watts. It's on there somewhere.

Not without knowing the watts. That is what matters most. You want about 40 watts.

for my 20g long tank, i'm going to buy a 48" long shop light and 2 T12 GE plant and Aquarium blubs. $20. can't beat that, and i'll end up with 4wpg. and the portion of the strip that hangs off the edge of the tank i'm going to use for my non-aquatic plants.

RockabillyChick said:

for my 20g long tank, i'm going to buy a 48" long shop light and 2 T12 GE plant and Aquarium blubs. $20.

Click to expand...

I would stay away from the Plant and Aquarium and simply buy the Philips 'Daylight Deluxe' bulbs, they are rated at 6500k- ideal spectrum for plants.

If you want to have a little more fun, try ODNO

High output T-5's throw way more light than their wattage suggests. Go to reef central and read up. I bet you could get away with one full legth HO T-5 and get great results.

I personaly do not believe in the watts per gallon rule. I bought into it but I think it is a poor thought out rule.

So If I toss a 30 watt High Intensity Discharge (HID) light on top of my 20 gallon tank I'm only getting 1.5 watts per gallon it it will likely be brighter and put off more light than a 100-150 watt halogen bulb. so it would give me the same results as what about 5 watts per gallon? Different lighting technoligies are servearly more efficient than others!

Rule does not work for me. NOT AT ALL. Lumens and Intensity would be a BETTER way to rate lights but still not perfect.

I think you will be fine with the coralife unit. I had one on my 10 gallon and it worked great, now I'm using it on my 20 gallon and it still works great. Mine is 28 watts & 24 inch, it should say on the box, they swapped the bulbs for full spectrum bulbs instead of the blue one for marine tanks it came with. I did add teh stock flourescent light to it, it says it's 15 watts but it is not even 1/2 as bright as teh corlife unit with it's good reflector.

If your talking about the one with 3 bulbs that should work awesome. just kinda $$.

DIY CO2 should be enough for your tank.

This is of course pending on yoru selections of plants.

I have an unidentified plant in my vivarium, tons of crypts, some micro sword and wisteria,lucky bamboo, anubias, all growing with no CO2 (very light doses of excel) and the stock bulb. (course theres only a few gallons of water in it...)

Just my opinion...there i have said it.

If I had the free time i would make a 15 watt LED aquarium light to prove the rule totaly incorrect. It would have the efficiency of a HID but better spread, and you could even select the whitness level just like you can with flourescents and never burn out....I just don't have the time.

The rule is for NO flourescent lighting. It does not apply to other types of lighting. Which means you wrote a whole lot to prove a point that was allready accepted

Yeah, that fixture will work for you. T-5's are a bit brighter then PC lighting. I may be wrong on this though, but isn't that fixture a LOT more expensive then, say, the 24" single PC light by coralife? T5 looks like a technology that is very usefull in reefs where you need more like 10 wpg and need to cram a lot of bulbs in there, but more expensive when you only need one or two bulbs.