Math question?


Reefing newb
Someone plese tell me that this is wrong. Here in Clovis CA where I live we pay $0.21 per KWH (keliwatt hour) for electricty. Well theres 1000 watts in 1 KW. Metal Halides are 400 watts each and I would need to run 2, so thats 800 watts. So 1000 divided by 800 is 1.25. So thats 1.25 KW for both lights. 1.25 mutiplied by $0.21 is $0.26 per hour mutiplied by 8 hours a day is $2.10 a day. $2.10 mutiplied by 30 days in a month is $63.00 a month just to run the lights. This is not couting what it takes to run the sump, protein skimmer, uv sterilizer, light timer, return pump, heater or powerheads. Did I do something backwards or is this really right cause $63 seems alot just to run the lights 8 hours a day, not counting how much more its going to cost to run everything else that needs to run 24 hours a day.

Please let me know as my dreams of having a saltwater tank just died I think.
800/1000 =.8 kw x $0.21 =$0.168 17 cents x8 hours =$1.34 per day x30 days
=$40.32 still not cheap but not as bad as $63.You might end up the same nano boat as me.My electric bill is good but a fat reef tank like you are planning is better.Also for 90 gallon you cvould just use 2 250 watts plus 2 96 watt actinics
=692 watts =7.6 watts per gallon
Well I called my LFS and they said for that tank I want all I would need is (2) 250 watt Halides. So thats 500 watts of lighting. Useing that same formula would be

500/1000 = 0.50 X 0.21=$0.11 X 8 HRS = $0.84 PER DAY X 30 = $25.20 PER MONTH.

I can handle $25 a month but now the 300 watt heater comes into play.

300/1000 = 0.30 X 0.21= $0.06 X 24 HRS = $1.51 PER DAY X 30 = $45.30 PER MONTH

So now its at $70.50 just counting the lights and heater. There's still more things that are going to be pluged in and running 24 hours a day like the main pump and protein skimmer. Now if this is right I'm not sure if I could handle that. I'm looking at $100 a month just for power and maintence.

Now I've had people with bigger tanks and more lighting tell me that this has to be wrong because they don't pay nearly this much for theirs. People with 125 gal and 200 gal tanks are telling me that they pay like an extra $40 a month total for their tanks. If I was paying an extra $70 a month PG&E and Maintence thats cool, but $70 just for PG&E isn't. I don't want to go with a smaller tank cause I know I'll end up wanting something bigger. I'm just trying to make sure I can handle this before I start buying things.

I think I'm going to have to call the power company and see if I'm figureing this right cause I've got some people saying yes and others saying that when the output wattage is broken down to wattage used that its a lot smaller figures. I mean the heater for my house doesn't cost me that much.
you only count the time the heater is actually on. it does not run 24/7. my system will run me apprx. 80 dollars a month electric and i have 1400 w of lights, two chillers and a lot of pumps and other stuff. so your formulas are basically correct but the time use is misleading. your equipemnt is not always going to run at its full load rated output. heater will only run maybe 10 percent of time and pumps do not draw a lot. also lights are not on 24/7. so I would be surprised if you went over 50 dollars a month maintenance and all. depends on how you set up. if you use electronic ballasts for the metal hallides less electricity will be used. instead of using a 300 watt heater, 2 100 watts for a 90 should do unless the tank is out side. you will only be heating the difference from the room temperature to 78 degrees and your heat loss will depend on room temp, ciculation, and fans. so it is impossible to determine exact cost as there are too many variables. The people you know that have told you how much it costs them should give you some idea as to what your cost would be. There is some cost to be had for sure but I do not think you are comming to a reasonable conclusion due to the fact that time use has to be considered. hope this helps.
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Yes it helps more then you know. Thank you very much. I decided to back away from the 90 gal tank though. I found a 75gal tank that I pretty much feel in love with. LOL. And My LFS said I can use the Aqualight Pro HQI with (2) 150 watt Halides, (2) 96 watt Fluorescent Actinics and (3) lunar lights, or I can just get the one with the (2) 150 watt Halides.

Does anybody have any experience with these lighting systems. I'd like to hear anyones feedback.

Oh yeah I found a online Calculator that you enter your KWH and the wattage each peice of your tank uses and the hours they run and it will tell you the cost per month. Its made just for fish tanks. If anybody wants the link let me know.
that could work. im using dual 175 MH, with dual 48 inch vho actinics. but you could have used to same setup on the 90 gallon. or t5. The guy i bought my mh from switched to t5 like 2 months ago. he has no sps, but he does have a nice deresa clam.
Another thing you can try is with my FOWLR 170gal tank witha 45 gal sump. I use 1x 300w heater and use my MAg 24 for the second heater since its a whopping 250 w its also heaating my water being a insump pump to run my skimmer. HTH

Just to let you guys know up in canada is cost me around 25-35 dollars if that to run a full blown reef 225 gal :Cheers: sorry had to rub it in
I do agree the heater will only need power when the tempature drops.Halides will help keep it off.Also Cali the weather stays pretty warm(I am comparing to the Mid west were I grew up)So if the house is warm inside the heater will stay off more.
I also forgot to mention you need to check out the running wattage draw of the halide ballasts and base your cost on that not the bulb wattages.

I had no idea I pay that much just for one tanks lighting. I have a 55 gallon reef and I have a 40 gallon guppy tank, a 20 gallon snake tank, 10 gallon sick tank saltwater, 5 gallon sick tank freshwater, 3.5 gallon brime shrimp tank and my son has a 15 gallon hermit crab tank. They all have lights heaters pumps ect and all run 24/7. I don't even want to think of how much of my bill goes for pets.