The picture below shows my water feature of the 3 spill pots.
This picture shows my pump setup.
The one on the left is the pump for the feature. It is a Pentair Challenger High Pressure CHII - NI - 1 1/2F. As you can see, the (3) outputs to the individual pots are severely throttled back. This is way more pump than needed for the application.
I'm considering swapping that pump out for a specialty waterfall low head type pump. However, I have a couple questions.
1. How do I size the waterfall pump? There's not much vertical rise. The highest pots is about 42" above the water. Without measuring the head, I would imagine it's in the lower range of the waterfall pump capacity. But for flow, do I dial in the pot flow where I like it, then get a 5 gal. bucket and figure out the rate of flow by how long it takes to fill? Seems kinda simplistic.
2. Do the economics exist to make this swap? This thing doesn't run a lot. Maybe 35 hours/week worst case if I run it all day on the weekends. We have time-of-use power so our off-peak rate is under $0.10. That's around $5 week savings between the existing 11.2A pump and a new 4.8A pump. Low end, new pumps are $500 so we're looking at a two year break even. Now if my existing pump were broken, there's no question I'd just be dealing with question 1. But I have an existing pump that 'works' but is just not as efficient as it could be.
I understand there will be a lower noise benefit as well. And that's worth something.