We have a header tank, every few weeks we pump uphill to it (22,500 litres). When it was installed, our plumber and others informed us that it was more efficient to have the pumped water going in at the bottom of the tank, rather than a pipe going up the side of the tank and then in at the top.
Soon we will add another tank, same size, and the 2 tanks will be plumbed together at the bottom of each tank. In effect, we will be pumping uphill (soon) and pushing against 2 tanks x 22,5000 litres. Wouldn't it require less power draw on the AC water pump to simply go up the side of one tank and in at the top ??
Note: When the first tank got delivered, although we ordered a 50mm inlet, they made a mistake and made it 40mm. I realise the friction loss is minimal there though.
So, should we pump in at the bottom or in at the top please ?