I ask because we all know that or should know that cartridge filters go to 10 microns. With that flakes or minute particles are still visible especially under light. DE filters go down to 5 micron and the water appears polished.
If you were to take the 95% of the load off the DE filter with a cartridge filter which easier to clean, then DE filter which is more difficult to clean it will last considerably longer between cleanings.
So I have assume from the responses to date no one has ever tried it.
I have three pools.. One of them has a large cartridge filter and the other two have DE filter.. All three have tiny "floaties" that can only be seen at night with the light on. I'm sure it is somewhat subjective, but I can't tell any difference in the water quality, or sheen, between all three pools.
I don't know of anyone that has tried your idea, but other that an increase in backpressure, I doubt that it would have any downsides.. I also doubt that you would see any real visual improvement in the water quality.
If I were going to to it, it would make sense to use the largest filters possible.
You have a fair question. I was just trying to understand the why because we get MANY folks thinking their filter needs work/help when it’s the water instead. Years and years worth of PBs / Pool stores convincing everybody that the pump/filter clears algae, not the chemistry.
And good on you for wanting to take it further, but you’d be hard pressed to see any results.
If mechanical filtration was equal to DE then I can see no reason for
DE's continued existence. You're right it is subjective. Kind of like acquiring a taste for fine wine. I have used both on various pools and can tell the difference, although I wish I couldn't. I suppose those that have never seen the comparison would would be satisfied not knowing the difference .
I agree in using as large a pump and filter as practical (budget permitting) in all cases. This allows the pool to recover from an event such as a dust storm etc rapidly.