A laudable idea.
I approach the problem from another angle. Think about it... if one's wash water looks murky in any way, one is "washing" with an abrasive solution, grit guard or no grit guard. It is the very fine "grit" suspended in the solution which turns one's wash water murky and brown. This occurs quite rapidly, if one wrings one's dirty sponge out over and over in the same soapy water source as used for washing. (I see folks do this all the time and quite frankly it amazes me.)
That is why I use two buckets during washing. Bucket A is a two gallon size and contains the clean soapy water. Bucket B is is a five or ten gallon size and is the sponge rinse bucket. it is filled as near full as is practical with clear water. During the wash, a.) never does a dirty wash cloth or sponge go back into bucket A (clean soap solution) unless first having been thoroughly rinsed out in Bucket B, and b.) never at any time does one "wring out" excess soap from the sponge or cloth back into Bucket A.
Simple, easy, and one's soap solution will not become murky and abrasive.
For a simple wash, expect to change the water in B at least twice, because it too will become abrasive, though at a much slower rate since ten gallons of water represents five times the volume of the two gallon soap solution bucket. Since the rinse water is not as obscured by soap suds, it is also more obvious when the rinse water in B requires changing.
This simple practice significantly reduces grit from one's soap solution, and is particularly effective on fragile lacquer finishes.
