Size of pump for 50,000 litre pool

[fyfin]

We have a small pool 8 x 4 mtrs and less than 1.5 mtrs at deepest end. I have calculated volume at 50,000 litres (or less). Now that electricity is expensive I wondered why I have a 1.2kW pump when the communal pool (where I am President) has a pump of 0.75kW and is bigger than my private pool.
Is there something I'm missing. The pool next door is also 0.75 kW and again his pool is bigger and deeper that ours. One difference is that I have no vacuum point so use one of the skimmers and seal the other one but I can't think that should make a huge difference.
Any advice greatly appreciated as I'm thinking it might be worthwhile to change the pump for a lower rated one.

[northandsouth]

There's a some factors to take into account, if I remember rightly it's about circulating the volume of your pool in 6 hours, maybe it's 8, can't remember which one off my head, I'm out and about at the moment. Also the size of the sand filter but from what I can make out a 750w should be OK for you. There are some calculators available online to be certain before choosing.

[fyfin]

I had a word with someone who does pools and his idea was to leave the pump but simply run it for less time. So far seems to be working fine. The pool is in the shade in the afternoon so I've never had a problem with algae.