Blue skim mate

[thatmanMIKEson]

Might you try skimming dryer— not so wet— and see whether it makes a difference? (Although to be honest, I don’t know that that necessarily answers any questions about the cause.)

why do you say dry? wet would take the most of the mystery blue stuff out the quickest . right? i assume he would like to get the blue stuff out quickly...;

but just look for something blue its not the water and fish poop is brown to green, most detritus is green so any other colors you have something in the water breaking down and the skimmer is doing its job but i would get rid of blue stuff you dont need and skim wet till it goes away...

 

[Kaboobie]

Does that look like the blocks that are at the bottom of your sump? It says it's fine for saltwater if so but not recommended for reef use. I'm guessing it's just a dye that they use for whatever reason. If you don't have anything in the aquarium yet, then you should be able to just pull all the dye out before too terribly long. If you don't want to risk it just pull it out and do a water change and get some media that isn't dyed.

 

[Panicked Reefer]

Yes I believe that's it.

 

[Kaboobie]

Yes I believe that's it.

some carbon should be able to pull that dye out.