Interesting. I talked to the Triton folks when I filled my TR-140. The instructions called for pea gravel as well but were VERY unclear as to whether it was essential.

My end result was to not use the gravel. No one could tell me it was essential in a way that convinced me. The pros in my area (I called three) don't use it and two hadn't heard of it.

I sorta' ended up thinking the sand filled around the gravel very quickly, not doing much to alter the filtering characteristics.

This is not to dispute "Waste's" thinking but simply to post how I arrived at a different conclusion....I have no idea if one makes more sense than the other.

Matt, You finally found a scenario where I agree with replacing the sand (We've discussed that before, I think) It would be such a hassle to salvage and reload the old sand.......new in the bag makes more sense.

Al, my good ole' Triton has a clever valve on the bottom that allows you to release only water or both water and sand. My assumption is that in the "sand" position it would allow you to wash the sand out with a hose....seems like it wouldn't be too bad but I've never tried it. Am I missing something?

Dave S.