Electric Bill

[ReeferMadness]

I am debating if I should switch from t5 to metal halide and just out of curiosity, how much would a 400 watt m.h. raise my electric bill per month. I kind of assume the jump would be nominal considering right now I am running 324watts of T5. Thanks in advance.

[muddybluewater]

Are you going to have actinic supplementation? If all you are changing is 324w to 400w it should not be more than a few dollars.

[AlexKilpatrick]

The calculation is pretty easy:

1) Take the number of watts you have: 400

2) Multiply times the number of hours per day you run your lights: 10

3) That gives you the number of watts-hours per day: 4,000

4) Divide by 1,000 to get kilowatt-hours per day: 4

5) 1 kilowatt hour is around .06 (I think, check your bill)

6) Therefore you lights cost 4 *.06 = .24 per day to run

Adjust as needed. You can also get devices like the kill-a-watt that will measure it directly. This is a little bit of an approximation because there is some loss in the ballast, but you get the idea.

[+Eckreef]

5) 1 kilowatt hour is around .06 (I think, check your bill)

Alex,

Who is your electric service provider? I have been shopping this recently and the cheapest I could find was around 10 cents/KWh

[+ACampbell]

Don't forget, 400 watts produce a lot heat. I've owned them before, and if I do another big tank it will definitely be T5s. It may not be that big a deal now, when ambient temperatures in the house is lower, but come August you may be looking for a chiller.

[NonSequitur]

With a pair of 175w MHs my tank costs about $25/month in electricity to run (that's the entire tank, incl. pumps, skimmer, heater, cooling fans, etc.), but like muddybluewater said, unless you're going to use actinic supplementation you won't see a big change going from 324w of t5 to 400w MH, at most 100w difference when you figure in ballast inefficency, which could be offset by changing out 2 60w incandescent lamps in your house with 13w CF lamps if you want to look at it that way.

[doktorstick]

$.06!? Holy smokes! I'm like $.14 (so, for your calculation $.56/day, $17/mo, $205/yr).

[AlexKilpatrick]

$.06!? Holy smokes! I'm like $.14 (so, for your calculation $.56/day, $17/mo, $205/yr).

OK. I am not sure what my actual bill is. Now I am going to have to go check. But $17 / month is not a huge amount, especially in this hobby. The rest of your equipment is in the noise.

And the original question was about the delta between 324 and 400, which is almost nothing.

[subsea]

What was the point of changing to MH?

[muddybluewater]

Another question would be why 400w, and what kind of fixture/ pendant would cover a 55g tank (4'x?)? Wouldn't it be better to go with 2 lights? 2x 175 or 250w

[+ACampbell]

Shimmer?

[subsea]

Shimmer would be the only real advantage to MH. Because of the point source of the light you get shimmer. However, as AC has pointed out, you loose out on distribution of light in the tank. I happen to like some spots being more bright than others. It is more natural in my opinion. Also, I think it is more beautiful to accent a particular spot with sudelties of contrast. The downside of a point source light is that high demanding photosyntic critters can not grow everywhere. From my point of view, I consider this good. I like the contrast of bright and shading. From the point of view of commercial growers, I used 400W MH on a rail which moved the light on a slow ark back and forth. In my particular case, I had two 4' by 8' troughs set up for growout. The dollars saved on electrical consumption were substantial and paid for the rail track within three months. Another benefit from the point of view of a display tank, would be a constant changing sceanario with respect to light intensity and shade contrast. Whatever blows your skirt. It is your money.

Patrick