Black substrate at Menards...

[CHOMPERS]

"Lava Rock" is also coal clinkers, it just hasn't been pulverized to sand grain size. Lava Rock has been safely used in filters for decades.

 

[mithesaint]

Well? Did you try it out? Inquiring minds want to know!

 

[Ironmahn]

Yes, I have had a large goldfish, 2 paradise fish, pleco, and a large blue gourami in there now since posting this question. All is well. Only negative so far is that if it gets in the filter pump is sounds like it's crushing glass.

 

[CichofitAll]

Doesn't coal slag contain a lot of heavy metals? It may not be toxic to people based on the MSDM sheet but if it leeches metals into the water it may be pretty bad for fish.

This stuff is a serious no go! Please don't use it. There is no consistancy between batches/bags. You never know what's in it. I lost a breeding colony of HRPs to this ish.

 

[Ironmahn]

Well, I have left the fish in the test tank... but I decided to get 3M Colorquartz. I like the look much better, it has a fresh clean look to it.

 

[Ironmahn]

Don't use it... caused internal injuries to the fish!!

 

[WalterMelon]

What do you mean internal injuries? Did they start having bloody poops or something? Bleeding gills?