Copepod Population Boom

[BamboozleBean]

My tank has been running for about 3 and a half weeks, I got 3 very small pieces of live rubble rock from my LFS.
Practically in 2 days there are enormous amounts of pods covering the glass.
Not complaining just wondering why this happened.
It’s a 10 gallon bare bottom frag tank setup.

 

[Jason mack]

They've come with the live rock probably .....free gift ....