The suction side of the pump only has about 4-5' of head loss, and the pressure side has about the same which is where I got my 10' of total dynamic head loss from.
Too splashy mean the water is splashing OFF the sieve screen when it makes contact and then jumps big water bubbles down onto the waste tray. Those big drops of water disturb the trapped waste and help break it down quicker. There will always be some splashing but you will know what I am talking about when you get to that flow rate
The air inside the priming pot could be caused by a small air leak on the suction side of the plumbing as well as the normal dynamics that occur inside a vacuum container like the Zakki Sieve...
Air Inside Sieve…
There is ALWAYS going to be extra air inside the Zakki Sieve due to the oxygen level of the incoming water. Hopefully this will help to explain the vacuum dynamics inside the sieve…
Even if there was a perfect seal on all pipes, pumps, and filters you will still end up seeing some air going into the pumps leaf basket. The reason for this is due to the incoming water releasing the dissolved air inside the Zakki Sieve. At atmospheric pressure (everywhere outside of the Zakki Sieve and pvc pipe) the pond water will have a certain amount of air dissolved into the water. When the incoming pond water is exposed to a negative/vacuum pressure inside the sieve, it is no longer able to hold onto that dissolved air so it is released inside the Zakki Sieve container. This is only a microscopic amount of air that is released but over time it starts to add up inside the filter, which will create a larger air bubble and lower the water level inside the sieve. This issue has been designed for by drilling a small hole in the top of the pump suction pipe inside the sieve. As the water pump sucks out of the bottom of the sieve it also creates a very small water vortex just above that hole. When the water level is high inside the sieve, the vortex can not extend all the way to the water surface, but as the air bubble grows inside the sieve the water level drops low enough so that the vortex can reach the surface of the water. Then, just like the water vortex in your bathtub, it will slowly suck out the extra air, that is being released by the incoming water. This creates a self regulating water level. The amount of air being released inside the filter is determined by two main variables. The dissolved oxygen level of your pond, and the vacuum pressure created inside the sieve. The greater those numbers are, the more air that is released, however it should not be enough air to overwhelm a water pump unless there is an actual air leak in the pipes/valves/etc or the flow through the water pump is too low. If the water flow is too low inside the water pump, then the water will not rush into the leaf basket with enough force to push the air bubbles into the pumps impeller. The air bubble will continue to grow inside the leaf basket until it gets big enough to get sucked into the impeller. At this point you would notice a reduction in water flow and extra noise from the pump.