New 20 Gal Freshwater Setup

rebel101

Is it possible to add a layer of natural gravel on top of a layer of crushed coral?

james481

This is a freshwater tank? Is there a specific reason you're using crushed coral in the tank? If you're not aware, crushed coral (as far as I know, all types) will slowly leach salt and calcium into your water, and can change your water parameters in an undesirable manner. If you understand the effects of using crushed coral and are doing so for a specific reason, I can't think of why you couldn't put gravel on top of it, although the gravel and coral will probably eventually mix together. Also, you probably don't want too much substrate in your tank (again, unless you have a specific reason to do so, like running an under-gravel filter).

tophat665

Like James said, so long as you understand that the crushed coral will make your water nearly hard enough to sculpt over time - I put crushed coral in a filter to make my soft water acceptable for Tanganyika cichlids, f'rinstance - crushed coral substrate works the same way - there is no reason not to put a layer of regular gravel over it if you're so inclined. Do be aware that they will eventually and inevitably mix.

okiemavis

If you are keeping african cichlids the gravel will mix quite quickly- as many quite enjoy digging and moving around the substrate. However, it will work quite well. I know a shrimp breeder who always adds a bit of crushed coral to his substrate as he's found the inverts flourish with slightly harder water.