Also when my BiL had a 6ft marine tank it was costing him nearly
UKP10/wk, lots and lots of low wattage stuff soon adds up when it comes
to fish tanks - although the lights are usually the biggest load

It is a 6' marine tank, but it's been running 5 years and it's only recently
my electricity bill has gone up. Most pumps on the tank are about 5w each,
and only 4 of them in total. I'll check load though but don't expect it to
be much.