Brown sludge in bottom of fresh salt mixing container

[SandJ]

The tank is due for a water change. I just looked in the fresh water container (food grade white/opaque 20 gallon brute) and there is a reddish brown sludge in the bottom.

 

Instant Ocean salt

powerhead for circulation

heated to low 70's 

 

What is this?

 

And can I still use the water?

 

[pizzaguy]

Mine does it all the time if I leave it in there mixing for any length of time. No problem using it. I clean my can about every four water changes. Also clean pump and heater

[Origami]

You can use the water. It happens a lot. Sometimes it'll show up as a film on the surface or near the edges of your mixing container. My guess has always been that it's some sort of clay additive that's used to keep the mix flowing when dry. Over the long haul, your container will probably also see calcium-based deposits, too. No big deal.

[JeffG93]

It's anti-caking agent.  I haven't cleaned my brute trash can in... a year?  More?  Never had a problem.

[s2nhle]

i had it too when I added more alk and mag to the fresh mixed saltwater. I just clean it after empty it. No problem.

[SandJ]

Thanks everyone!