Submersible pump for small pond

Hi
does anybody know of/ or can suggest any effective small
submersible pump for recirculating water for a small pond (a couple of square meters (6 sf?) wide and some 40 cm ( just a little more than 1 foot) deep
to obtain a waterfall effect?
The height at which the water needs to be elevated is not very much, not more than 1 mt higher than the pond surface.
Regards

Your best bet, for long term use, is a "Magnetic Drive" pump.  These typically have all of the wires/electronics completely sealed.  Instead of having a motor driveshaft that goes into the pump through a rotary seal, these have all the stationary electrical parts of the pump sealed in epoxy, the impeller (the part that moves the water) has magnets embedded in it and becomes the rotating part of the motor.

Anyway, I've had good luck with Danner magnetic drive "Pond Master" pumps.  They last a long time and are simple to rebuild when they do wear out.  However, they are made in the USA so might not be available/affordable in Spain.

The depth of the water is mostly irrelevant to the pump, what matters is how high and how much.  Getting it 1 meter high is easy, but how much do you want?  Do you want a little trickle, or a 1 meter wide sheet of water 20cm thick?

You can estimate how much water you want by pouring a measured amount from a bucket onto your water fall until you get the desired effect, then see how many seconds/minutes it takes to empty the bucket.  A little math will tell you how many liters per minute you want.  Just be aware that most pumps are rated at the 'zero lift' capacity.  Raising the water 1 meter can reduce their flow by 20-50% or more depending on the pump.  What you want to find is a flow vs height chart.  If the pump manufacture doesn't have one available, then that is a good indication to look elsewhere for your pump.

Thanks Peter, for your advise.
I'll look into those pumps
Antonio

Peter, what does it mean that

Peter VanDerWal wrote:  most pumps are rated at the 'zero lift' capacity.

Does it mean that the amount of liter they produce is calculated at the same level as the water exits the pump?

"what does it mean that most pumps are rated at the 'zero lift' capacity."
The flow a pump can generate--expressed in unit of volume per unit of time--is inversely proportional to the height it is lifting that water. Typical ratings on the box will tell you the maximum flow--assuming, without stating, zero lift--and often the maximum lift--assuming, without saying, negligible flow. A company that wants to inform a knowledgeable user will include--in the manual if not the box--a chart that allows the user to calculate the actual flow at the lift needed. That said, without such a chart you'll probably be satisfied with a pump with a maximum lift more than twice what you need and a maximum flow more than twice what you need.

Antonio Scotti wrote:Peter, what does it mean that

Peter VanDerWal wrote:  most pumps are rated at the 'zero lift' capacity.

Does it mean that the amount of liter they produce is calculated at the same level as the water exits the pump?

Just to make sure it's clear, "Zero Lift" means the water exits the pump at the same level as the top of the water that is supplying the pump.  It's basically moving it from one spot to another without any change in elevation.