In my opinion you will always collect some water with time. As I see the filter screen construction water and dirt drop down into the cylinder out of a small hole in the base of the fine mesh filter. Since it has the audible water present warning it is not as important how clear the cylinder remains.

In fact it may even be replaceable with a cylinder from a labratory glass place was one thought of mine if required at some point. Should not cost much if your pleasant.

Now the amount of water collected varies from none to massive in my experiences of driving volkswagon diesels for 15 years. For periods you may even seem to accumulate next to nothing. It is also going to accumulate dirt in the bottom in my opinion over time. That saves your main filter the job. Much more will be collected if installed before the pre filter. Consideration might also be given to elimination of the pre filter with this model installed.

Basically the formula does not change. You are better off with a water separator than without one. With the auto warning device if someone pumps a lot of water in you will find out very early. This increases your chances of getting the fuel changed out free and new water free fuel installed.

It really does not matter what brand you buy. People should have water separators. With a water present device is also far better than without one. .