watts per gallon?

[choupic]

I want to know how may watts per gallon I have. Where can I find a caculator or a chart to figure it out. I have a 55 gall standard size and lighting is a Nova t5 216 watts.


thanks

 

[schoeplein]

218w / 55gal = 3.91 w/g (general)

This of course is obviously offset by the depth of your tank.

 

[sir_dudeguy]

watts per gallon is a horrible rule to go by tho imo. For example 100 watts of pc lights compaired to 100 watts of metal halides...theres no comparison lol. The MH is going to be waaaay stronger. It penetrates more water, meaning that you could keep stuff all the way at the bottom. Where pc's dont penetrate so good so you could have like 20 pc bulbs over a single tank, but it still might not be enough to grow stuff at the bottom. Pc's are only good if the tank is rather shallow.

 

[roka64]

watts per gallon is a horrible rule to go by tho imo. For example 100 watts of pc lights compaired to 100 watts of metal halides...theres no comparison lol. The MH is going to be waaaay stronger. It penetrates more water, meaning that you could keep stuff all the way at the bottom. Where pc's dont penetrate so good so you could have like 20 pc bulbs over a single tank, but it still might not be enough to grow stuff at the bottom. Pc's are only good if the tank is rather shallow.

I agree, but it is like the inches per gallon and LBS of LR per tank. It is the best way, with all the variables, to generalize an answer.

 

[sir_dudeguy]

ya you got a point there i guess. Like say you're starting...oh...a 55 gallon tank... Generally you'd want to go for like at least 6w per gallon of PC lighting right? and then you look at how tall it is and adjust your lighting from there. If its only 12 inches tall (that'd be a weird 55 tho lol) then you could prolly get away with just some 65w bulbs and not have the 6w per gallon. Where if it was really tall (just say like 25 inches) you'd need to bump that up to at least t5's. idk...i just dont like those lighting "rules" cuz they kinda give newbies a "false" information. YOu might have like 10w per gallon but if its too tall of a tank it wont do you much good.

 

[roka64]

True, but those variables also include salinity (the higher, the more dense the water, thus different spectrums of light might no penetrate to certain depths), how much LR, where the tank sits (in direct sunlight, or a dark room). The sam goes for flow, this depends on how much LR, how it is positioned and such. I think those are generally decent guidelines. I guess the expectations should be set, that they are not written in stone and are lose guidlines, at LEAST a bare minimum or a decent average. How does that sound?

 

[melosu58]

I agree that the watts per gallon rule is shaky but as Scott said it is a way to generalize esp to new people that would not understand par and intensity. Let them get this rule down and as experience plays in they will more grasp the concept of lighting.

 

[flanque]

Yeah I was looking at my smaller tank and my larger one, then thought... hmm, what if I could get the same wattage over that tank.. I'd have a huge WPG.. that got me thinking.. so what if I put all my corals in the top 1/3 of the water column?

Would that mean..

60 / (55 * 0.333) = 3.3 WPG?

That seems much better than my current WPG of 1.1 (60 / 55)...


That also got me wondering about the rock in there, since that reduces the total gallons of water..