switch to suction?

[brent.roberts]

I'm pretty astonished at the $2176 energy cost. What is your power cost per kilowatt hour. Up here ours is about 5 cents. At that rate its aobut 43,500 KW / hours and that is a bunch.

If you switch from a cartridge filter you will need to run more hours to get the same filtering on a sand type filter. The cartridge type takes out more and finer debris. I have heard some claims about Zeobrite but I have not heard any reports from forum members that it lives up to the claims.

A switch to a two speed pump makes sense.
A lot less energy.
Better filtration at lower flow rates
Your cartridge will be easier to clean because the lower flow rate will result in lower velocity impact of debris on the filter and it will flush easier.
Quieter pumping and a few other benefits I cannot recall just now.

I agree about the the elbows. It is likely a waste of time, especially if you go with a 2 speed pump. True infinitely variable speed pumps are very expensive and the drives have some electrical inefficiency built in. ( frequency inverters) You don't need that if that's what they are proposing. But there are some folks who call a two speed pump a variable speed pump so you need to clarify what they are talking about. Inverter motors can whistle or whine a lot if they are not tuned properly. ( we use hundreds of them in the machinery we build )

A robotic cleaner will have a huge impact on the frequency of filter cleanings or backwashes.