Well, here what happened to me:
At some point I was talked into replacing the sand (after 4 years) for glass. Let's just say I was tired of fighting algae and the EcoSmarte folks after telling me all kinds of good reason their system did not perform as promissed, when having exhausted them, said that my sand is bad (yeah right, after 3 seasons they kept telling it to me).
So, when people came to repace it, they took out sand, took out the lateral assy, and though it was perfectly fine after 4 years, they insisted it had to be changed. Extra money. It did look different color-wise, otherwise was the same.
Athis happened mid-season, in July.
Putting glass involves first covering laterals with gravel, then the glass goes on.
Then it worked one more full season. That is, 1.5 seasons.
Anyway, next season I opened the filter to clean the top and saw that new pipe cracked longitude - wise.
I ran that season with this pipe. I figured, it would do some filtering. It did.
Next season I opened it...a piece of pipe above the sand was gone somI realized it will do very little filtering, so I tossed the glass, the lateral (it was fully crumbling) and replace it all. I am still not sure if it was the pipe type, or the glass, or....dunno.