Crushed oyster shell and coral calcium

[Elrodg]

Ok so I have about a 50 lb bag of crushed oyster shells and powdered coral calcium.

Would it be beneficial to add this to my sand bed or fuge?

 

[blanden.adam]

In a word, no. Oyster shells and powdered coral calcium are primarily aragonite, which is insoluble at reef pH and is roughly the same composition as your sand anyway. So, at best it will do nothing, and at worst you will have cloudy water form the powdered coral calcium kicking up in the flow

 

[Elrodg]

Maybe I should've elaborated a bit.
I just built my sump and was thinking about using it as a base for my dsb

 

[blanden.adam]

If I wanted a DSB, I'd just use a small grained sand. Idk how well those products would work, but I can't say they wouldn't.

 

[Elrodg]

Well basically I was thinking as just a base. Maybe an inch deep over my 5-6" dsb

 

[Elrodg]

Most of my experience was in freshwater. Plants and such. And we used a dirt base capped with sand and gravel to create a cryptic zone of sorts.
Am I just still thinking along the freshwater lines? Or is the principle the same for salty

 

[bertoni]

The comparatively large grain of some products like that makes them capable of collecting a lot of organic debris. I ended up throwing away my crushed coral for this reason. In addition, I wouldn't expect a DSB to function well with such a layer on top.

 

[Elrodg]

No on bottom. As a base.

 

[bertoni]

As a base, it'll work it's way to the top over time. Even at the bottom, it won't work well as a sandbed due to the large grain size.