Another ID post

[Rmckoy]

Not sure what it is .
My refuge bulb blew so had to replace it with another grow bulb . But this one is a full spectrum led .
more white compared to the old pink one .
Noticed this in my sump and curious what it is
It has to be around

0.500” in length

 

[Rmckoy]

Because I’ve never saw anything like it . I removed it .
It’s a hard shell , with 2 holes .
one at each end