# how many watts per gallon



## MABJ (Mar 30, 2012)

I'm not sure about your stock system, but buying something new may be a necessity. The 30 watts aren't going to cut it, and they probably aren't even in a good spectrum. 

Research LED lights, finnex lights. 

I'd also ask you to figure out if your tank is high or long. 


From MABJ's iPhone
2G Fluval Spec ~ fauna and flora in the works!


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## thelsegse (Jun 7, 2012)

If it uses the regular screw in bulbs you could switch them out for cfl bulbs.


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## dfish2077 (Oct 2, 2012)

Hi my tank is48" long. I've been reaserching t5 ho fixtures and builds. I don't know about led lights.just seeing if there is a cheaper alternative than going out and buy a 48" t5 ho hood and lights thanks for your help


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## akdylpickles (Feb 21, 2011)

Cheapest route would probably be PC lighting or T5 HO IMO I'd go with the T5. With T5 for a low tech setup you could go with just one 48 in bulb.


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## Sotty (Aug 31, 2012)

So just as an FYI the WPG rule doesn't work. This is because a watt of power going into a t5, t8, t12, pc, MH, LED will all produce different amount of light. Also even within the same bulb type the amount of light reaching the substrate (which is what we generally care about) is affected by individual ballast driving the bulb, reflector quality, and distance of bulb from substrate. So needless to say there are a lot of variables, but luckily there are really smart folks around here who have made some really awesome threads that have helped me.

Here is a thread discussing PAR data and how to actually determine the amount of light you have/need.
http://www.plantedtank.net/forums/showthread.php?t=184368

Here is a quick chart for popular lighting types and distances from substrate.
http://i.imgur.com/RbWzU.jpg

If this is your first foray into planted tanks shoot for low-medium light level so won't have to worry about co2 at startup.


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## TexasCichlid (Jul 12, 2011)

Get your plants first, then upgrade the light. Finnex makes a couple nice 48" LED options now that are very reasonable. Light is generally the last thing on the list of things you want to upgrade before getting everything else in order, as it's usually better to have lower light than too much light.


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## Vidivici21 (Oct 24, 2011)

I have 2 32 watt t-8s over my 55 gallon and it seems to be doing great. (no Co2 or ferts) You can get a shop light that does this for around $10-$20. You would also probably need to diy a hood, but it would most likely be cheaper then out right buying one.


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## Diana (Jan 14, 2010)

A very good alternative to lighting is a fixture available at Home Depot. It is a shop light, 4' long and has a diamond plate reflector. PAR on this one is pretty close to some of the T-5 bulbs, but it uses T-8 bulbs. That reflector is very efficient. 
Get bulbs that have lots of the light that plants need. Plants use more reds and blues. Since people see more yellows and greens, bulbs for people tend to be too low in the reds and blues for plants. 

Watts per gallon worked OK for T-12 and T-8 bulbs, but you also have to look into what color light they are putting out, and the quality of the reflector. If you can get something closer to 2 watts per gallon that is more like low light (if the reflector is low quality) or more like medium light (with a good reflector). 
Definitely look over all the PAR info, too. That really is the best way to judge lighting. That is a direct measure of how much light that is actually useful to the plants is getting into the tank.


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## Sotty (Aug 31, 2012)

oh also didn't mention this above specifically and others have implied it, but color spectrum of the light matters as well. So if you go with fluorescent tubes shoot for either 6500 or 6700K (kelvin) lights.


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## kevmo911 (Sep 24, 2010)

Sotty said:


> oh also didn't mention this above specifically and others have implied it, but color spectrum of the light matters as well.


No, it really doesn't. Not to the plants, anyway. A 3k bulb versus a 12k bulb will look completely different to you, but there's no solid evidence that says that plants care a whit either way. You'll see more yellow at one end and more blue at the other, but plants will see happy light all the way across. Just avoid actinics, as they're a bit beyond what plants appreciate.



Sotty said:


> So if you go with fluorescent tubes shoot for either 6500 or 6700K (kelvin) lights.


That's good advice. But shooting for 10k's would be similarly good advice. The median/mode bulb choice around here seems to be a 50/50 mix of 6500's and 10k's. Mostly, you can't go wrong on temp choice, as far as plants are concerned. But you should probably pick a color that you like.


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