carbon filter question

[alan]

i bought a carwash about two years ago and decided to change out the gravel and carbon. when i unscrewed the head there were small white plastic pellets floating on top of the water. i stuck my finger down in the neck of the tank to see how many pellets were floating on top and there were at least three inches maybe more. i went ahead and put the head back on until i can figure out why those pellets are in there. has anyone out there ever come across this.

thank you

 

[MEP001]

I know I've never seen that. What do they look like, hard plastic or Styrofoam? What keeps them from flowing through the head with the backflush water?

 

[alan]

these are hard plastic pellets a little less than a quarter inch in diameter. i dont think they can flow thru the head there is a screen up near the head that stops them.