How Much Depth for Sumersible

[Obx_guy]

Good Day all.... I appreciate all the information provided by members here... definitely the best solar source on the web...
I had looked at using a solartech SPMD4350HS pump for a shallow well. Was ready to pull the trigger... but requested a manual just to verify installation.
To my surprise the manual stated that the pump should be installed at least 2 meters from the bottom.
I only have 1.9M of water since it is a shallow well. The literature says suitable for shallow wells and ponds.
So what do I believe.... should I be concerned??? I can provide 50cm below the pump to make sure I don't have a water level issue, since the pump is above the motor.
I have been clearing the well with a .5hp centrifugal pump that I have run for 10 hours without an issue providing 1650LPH.
Should I be concerned about this 2 meter constraint????
Regards

[Obx_guy]

Anyone have any thoughts on this....

[azdave]

I doubt any manufacturer will recommend the pump be so close to they bottom but 50cm is better than nothing. Seems like it is your decision to risk that choice or possibly ask on a forum more suited to DIY well installations.

[peakbagger]

A typical pump will run with just about any depth of flooded suction, the downside is if you can pump out of the well faster than it can recover than the static water depth will drop. In that case the pump will start to suck air and cavitate until the pump recovers. The usual "fix" is to drop the pump further down in the casing below the static water level and use the extra depth for short term surge demand. The alternative which is more efficient is to put a small volume positive displacement pump in the well with a capacity less than the recovery rate of the well. Then pump up to storage tank with second higher volume pump preferably with variable speed drive to supply actual demands. The PD pump down the hole is far more efficient than centrifugal and no worry about cavitating the pump.

[MichaelK!]

It's about sucking up muck and grit that's settled into the bottom of your well shaft. The manufacturer does not want the pump inlet that close to the bottom to keep that material as far from the pump as it can be. My pump is 115 meters down, so two meters from the bottom is trivial. In your case, it is not. It all comes down to how much you need to worry about grit getting into the pump/motor and damaging it?