# Electricity needed for tanks



## happysaz133

Just out of curiosity, anyone have any ideas how much electricity a small (35litre) fish tank would use up? My Dad is always moaning about electricity bills, but I would love to get a small tropical community in my tank. 

I realise they would need a heater, light and filter, so just curious really.


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## Guest

Without knowing how much you pay for electricity for each kW h, it's a bit difficult to give you a rough idea. However, a tank of this size certainly shouldn't use any more than 100w for all of the major components (e.g. filtration, lighting, heater) combined, and that would add virtually nothing to your bill. That is of course if things are kept fairly basic.


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## Blitzgreen

i'm sorry chillinator but i have to disagree with you there!

i have a low unit cost of 14 pence a unit
using 100watts is 34 pence a day
£2.35 a week
£122 a year

for that size tank you will need a 25watt heater (which will heat up to 40litres) 15watt light and 10-15 watt filter(which will filter 20-60litres). Sure you could get more power consuming components but these are the bare minimum i recommend and that i have seen in shops


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## Guest

Blitzgreen said:


> i'm sorry chillinator but i have to disagree with you there!
> 
> i have a low unit cost of 14 pence a unit
> using 100watts is 34 pence a day
> £2.35 a week
> £122 a year
> 
> for that size tank you will need a 25watt heater (which will heat up to 40litres) 15watt light and 10-15 watt filter(which will filter 20-60litres). Sure you could get more power consuming components but these are the bare minimum i recommend and that i have seen in shops


£2.35 a week is technically peanuts by fishkeeping standards, 100w was given as a basic upper threshold, depending on how much equipment the OP is going to use and the wattage of each component. If the OP desires to keep difficult species of aquatic plants, then the lighting will need to be increased, possibly going upto T5 power compacts that can use in excess of 30-40w per tube. However, even with higher lighting the total amount of electricity being sucked up by the equipment shouldn't exceed 100w. I was erring on the side of caution.

In contrast, a 6ft reef tank consuming in excess of 600w of electricity would add around £60-70 month to your bill on your power tariff for example.


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## Guest

Blitzgreen said:


> i have a low unit cost of 14 pence a unit
> using 100watts is 34 pence a day
> £2.35 a week
> £122 a year


Your working is correct, but is your calculation based on the equipment being on constantly? Remember, that not everything would necessarily be switched on 24/7.

Let's imagine that we have a filter that uses 15w, lighting that uses 35w and a heater using 50w of power to give a total of 100w. Now let's calculate the cost of this equipment being switched on for how long it really would be switched on for based on how much you pay for your electricity per unit.

Filter - switched on 24/7. Power consumption 15w (for example). 24hrs x 31 days (as an average) = 744hrs/month. 15w = 0.015kW. 0.015kW x 744hrs = 11.16kWh. 11.16kWh x 14p = 156.24p/month. The lighting will cost £1.56 to run for one month, based on the unit being switched on 24/7.

Lighting - switched on for an average of six hours per day. Power consumption 35w (for example). 6hrs x 31 days (average) = 186hrs/month. 35w = 0.035kW. 0.035kW x 186hrs = 6.51kWh. 6.51kWh x 14p = 91.14p/month. The filter will cost 91p to run for one month, based on the lighting being switched on for a photoperiod of six hours per day.

Heater - this will run intermittently, as the thermostat inside the heater will switch it on and off depending on the water temperature inside the aquarium. However, as an average, let's say that the heater runs for 12 hours a day. Power consumption 50w (for example). 12hrs x 31 days (average) = 372 hours per month. 0.05kW x 372hrs = 18.6kWh. 18.6kWh x 14p = £2.60/month. Based on these averages, the heater will cost £2.60 to run for one month.

Total cost for average electricity consumption per month = £5.07. Total cost of average electricity consumption for one year = £60.84.

If the equipment uses less electricity, the cost would be even lower.


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## happysaz133

Blitzgreen said:


> i'm sorry chillinator but i have to disagree with you there!
> 
> i have a low unit cost of 14 pence a unit
> using 100watts is 34 pence a day
> £2.35 a week
> £122 a year
> 
> for that size tank you will need a 25watt heater (which will heat up to 40litres) 15watt light and 10-15 watt filter(which will filter 20-60litres). Sure you could get more power consuming components but these are the bare minimum i recommend and that i have seen in shops


Oh that's not bad at all!  I was imagining way higher. I guess I'll go ahead then! :thumbup:


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## happysaz133

Chillinator said:


> Without knowing how much you pay for electricity for each kW h, it's a bit difficult to give you a rough idea. However, a tank of this size certainly shouldn't use any more than 100w for all of the major components (e.g. filtration, lighting, heater) combined, and that would add virtually nothing to your bill. That is of course if things are kept fairly basic.


Thank you! You made me happy


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## hawksport

Made me sad I've got 750 watts of metal halides


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## Fishyfins

for what its worth, back when i had space for lots of tanks, i had a 200L tropical freshwater tank, and a 100L reef set-up, both with powerful external filters, 2 heaters each, and both with T5 lighting. the cost of both set-ups added about £200 a year to my bill. now i dont know the maths involved, nor can i remember the total amount of watts used in each tank (though it cant have been a small amount), but as i say, the basic cost for both, per year, was about £200. they arnt really all that expensive


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## tashi

Thread closed op has the necessary numbers, the rest of the posts were basically flaming other members


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