Yeah I have seen the same exact setup on a friend's pool before, only I think that they had a Hayward Super Flow 2 pump. For the last several years I've been trying to convince her to come over to the TFP methods, but she can't be bothered with taking 30 minutes out of her life for me to explain proper water chemistry to her, and has already gone through the expense of replacing her pool liner as of last year as a result of running extremely high chlorine levels for years by just throwing the trichlor Pucks in the skimmer basket as many as six at a time, and hiring someone to come in and maintain her pool lol..., she also installed a SWCG as of last year. My wife and I and our friends stay at her house up to 3 times a year, and when we stay there for the extended weekends I'm usually in charge of maintaining the pool. Funny.... 10 years ago I didn't know a single thing about pools and I was still the one attempting to try and figure her pool out.
I honestly wouldn't worry about the throttling. To go to the trouble of installing two ball check valves, glue and seal the pipes and valves, test for leaks, etc, just to throttle water flow for week or so to clear the pool utilizing slower filtration. Its probably not worth it.
Whether the slower filtration method works, it's really only in theory as far as I know. I can't substantiate scientific evidence-based proof for it.
I can only say I've tried it, and my reasons for trying just to even out pressure for longer pump time run at slower rates, just to see if it works because my pump motor is only one speed. Those are the trade-offs of slower filtration. It takes much longer to get things clearer. But slower filtration is only purposeful when you have efficient micron mediums like cartridge or DE to do it. Again this can all be variables depending on the power of your pump and setup. Some pumps are underpowered for the size gallons of pools, some pumps are overpowered for the size gallons of the pool. Pumps are typically depicted in GPH, or GPM, they have flow rates and it is also measured in square footage as well.
Once you are clear and water is balanced, that much amount of overkill filtration is no longer necessary.
I only do it because I have an above ground pool that's not that big, it's only 7200 gallons and my pump and filtration including flow rate is a little overkill. 1.5 hp Hayward Matrix Flow because I have a lot of debris falling into the pool cause I'm next to the woods, and the pool and my pump came with the house.
Try using the bags and see if it suits your purpose, and kindly let us know the results.
