Although the pump will use less power when turned back it only goes so far, for example the snapper can only be turned down to 75W and your pump could be around the 200W range for a minimum. Second your pump efficiency is best around the mid-range where flow curve intersects the power curve. For example look at the snapper flow chart:
The most efficient way to run this pump is at around 8 feet of head pushing around 1400GPH at about 100W. I'm just guessing here but that seems to be perfect for you which is why I recommended it. I would also bet the power you save in one year will pay the difference between your pump and this pump and after two years almost pay for itself. If the snapper is too small the same company actually makes another pump called the Dart which has slightly more power so not sure why that wouldn't have been the next logical choice.
In the end just trying to give you some useful information and advice as well as make sure others don't make the same mistake. Yes a little off topic but I think if someone sees an obvious problem it's good to point it out rather than ignore it. Justify it all you want but there are many good reasons why people don't use actual pool, jacuzzi, or hut tub pumps in this hobby. A lot of times these types of pumps are not meant for continuous use and they don't have the correct seals.
It's that kind of attitude which results in North Americans using 11 times the necessary carbon footprint. Yes not many aquariums are considered green but no point wasting power, two wrongs don't make a right. All my pumps are sized correctly and I've done essentially everything I can to reduce the power consumption of my aquarium. I also car pool which actually offsets the carbon footprint of my aquarium
I also thought you might find that fact interesting if saving money didn't, not trying to make anyone join Greenpeace or anything.