Trying to identify ... this (photo attached!)

[psumms]

Noticed a few of these in my sump last couple of weeks, seem to coincide with an outbreak of pineapple sponges and be growing on the glass and dark surface areas. Pretty sure they're not Tritoniopsis elegans or Nudibranchs. Seem to form a clear white tube structure that have grown to approx. half an inch wide. I don't think they are related to the pineapple sponge. Any advice much appreciated.

 

[Sparkymarc]

Looks like a sponge