Have you guessed what it is yet?

[atoll]

Am ready for the jokes so to your worst

 

[The Farmer]

Filter sock silencer?!

 

[atoll]

Filter sock silencer?!

Nope

 

[atoll]

Anybody?
Wouldn’t have an aquarium without one.

 

[mmorrison55]

Some kind of copepod habitat?

 

[atoll]

Some kind of copepod habitat?

Nice try but.... nope.

 

[keagan]

A media cup?

 

[atoll]

A media cup?

Na. Have another go.
Widely used in Europe in both marine snd FW aquariums

 

[StartingATank]

Protein Skimmer???

 

[atoll]

Protein Skimmer???

Nope, give it another shot.

 

[Privateye]

Does it have something to do with potential overflow from the filter sock?

Or maybe some sort of filter caddy?

 

[atoll]

Does it have something to do with potential overflow from the filter sock?

Or maybe some sort of filter caddy?

Not at all, sorry.

 

[Privateye]

Some sort of a cap to close-off one of the filter sock holders? Maybe not because you could just add a sock to the slot, but I suppose this might be quieter.

 

[atoll]

Some sort of a cap to close-off one of the filter sock holders? Maybe not because you could just add a sock to the slot, but I suppose this might be quieter.

Nope nothing like it, sorry.

 

[Sam7]

its a refugium light cover to keep the light spill away and keep the macro under water lol

 

[Sam7]

its a prefilter to keep your return pump clean and block invasive crap form getting back into tank

 

[StartingATank]

A cap to the sump so gorilla crabs and such wont get out????? Maybe to stop a fish from getting into the sump????

 

[Evil1]

Some sort of mechanical/ biological in sump reactor?

 

[BigDangler]

This where you hiding all your money??!!???! lemme know.. iso address

 

[atoll]

its a refugium light cover to keep the light spill away and keep the macro under water lol

Nope.