I just found this quote
check the Watts and do a quick calculation. To get from Watts to £ per year multiply the Watts figure by 0.9 as a simple approximation. In other word 50 Watts will cost about £45 per year, 80 Watts about £72 and so on.
If the pump box does not give a Watts figure be careful ... maybe the supplier is hiding a high cost factor. If there's no Watts but you see an Amps figure convert the Amps to Watts by multiplying the Amps by 200 for a comparitive annual running cost figure. If the Amp reading is 0.3 then the annual power cost would be about £60.
The watt figure should be found on the pump itself unless you know the brand and size in which case you should be able to google it,
the watt for the UVC (ultra violet clarifier) will be on the bulb itself unless you can google that too.