You can use a 2-way diverter valve instead of ball valves.
When you have two valves that must be opened or closed there is the risk that someone will only open one of them and deadhead the waterflow and damage equipment or plumbing. Best to have one valve to accomplish a bypass.
Here is what I am trying to do. I was thinking while I am at it, I could isolate both the heater and SWG. I only ordered 1 three way and 1 check valve for the heater. Now I am thinking the best way to do this would be a 3-way on each side of the SWG.
Circupool RJ45. My signature is off because my pump station is disassembled and I'm rebuilding. I track my balance carefully but my heater prematurely wore out. I'm on the north coast, it gets used a lot. Blows my mind the front of the unit says to install a check valve but installers don't do it. Now that I am rebuilding, I don't want to touch it again. My pool is closed all winter and it takes a minute in the spring to re-balance and clean it up. When my heater was leaking I had to shut the whole system while I evaluated the problem. In the end I took it out of the loop. I would have preferred to troubleshoot my system without shutting down the pumps. While I am at it, wouldn't it make sense to be able to take the swg off line while still running the pool? I would do it for spring cleaning, repairs, whatever. 2 way valves are cheaper Than 3 way, though maybe it doesn't matter since this is a permanent change.
I have a heater with a heater bypass and an IntelliChlor SWG cell. I have never needed to bypass or remove the SWG cell. I do bypass my gas heater at pool startup until I have the pool pH stable in the 7's and TA where I want it.
I see the reason for a heater bypass. I don;t see a reason to bypass a SWG cell.
A heater has a cooper heat exchanger that is sensitive to low pH. A SWG cell uses titanium plates that are not very sensitive to water chemistry.