Seachem Gray Coast Calcite Substrate, 7.7 lb

Basically a coarser version of Onyx Sand. Actually hard to tell the difference between the two. Needs to rinsed first. No big deal. Slate grey/ash in color. Easy to work with. Recommended.

I was glad I found this stuff. I previously used regular fluorite but needed to add crushed coral and cuttle bone which totally ruined the look. I now have this in my snail tank which will also have shrimp added soon. I also sprinkled a thin layer in the bottom of my daphnia cultures to provide some calcium as well. It's a great looking substrate!It is very dusty though! I tried rinsing it at first but it was clear that I was going to have a tough time getting to a point where the water wouldn't cloud up. In the end, I just went ahead and added it and then ran a filter with just filter floss to collect all the cloudy dust. Everything settled nicely, so even though there are still very fine particles, they seem to have settled in on the bottom layer. My water is very clear now and the tank looks very sharp with the clear water and dark substrate!

I love the look. It's been keeping my water very stable, shrimps are breeding.

This is the second aquarium I have used this substrate with. I have a mixture of Seachem Onyx Sand and Grey Coast (supposedly they are the same - just marketed for fresh vs salt). After buying a bag of each I can confirm that this is true.The substrate is a nice mix of coarse gravel with small and tiny pieces. The biggest thing to make sure that you do is to wash it. It produces a lot of dust that does not settle and will stay suspended in the water for ever. Give it a good rinse and you will love this substrate / gravel. If you do not rinse it - you will spend weeks doing gravel vacuums regretting ever using this.Plants love it and my trumpet snails love digging in it. Rabbit snails do have a harder time moving around on the smaller gravel though.You do lose a good amount of the bag through washing - maybe a quarter (25%) will go down the drain as you wash it - so if you think you need 2 bags buy 3. Best way is in a bucket with a hose or in a cup and your hand mixing slowly - most pieces will go through a strainer.

This substrate looks great in both my saltwater tanks. Love the color.

Crayfish and shrimps like it