Black Onyx Gravel

[Paradisius]

Just wondering as we are new to the saltwater community if Black Onyx gravel is really safe for reef set-ups. I removed my black granite from the tank once I aquired live rock. Was used for the start-up fish territory only and was told that the silicates would be very harmful to the tank in the long run. But it was short term only. When we were into freshwater, we found black onyx in a saltwater section but knew only of it's use in a freshwater tank. Have been reading online that seachem's black onyx gravel is safe for both freshwater and reef set-ups. Currently we have 90lbs of aragonite sugar sand and the live rock to go with. Has anyone used this in a saltwater set-up, and does it have to be reef?

Thanks for the heads up and advice is more than welcome.

[snaggle]

I have seen black sand in FOWLR and reef tanks before I am just not sure of the brand. As for it having to be reef, the short answer is no. The long answer is that reef is more sensitive than FOWLR so if it is good for reef then it is good for all salt water.

[jvision]

AFIK, Onyx does have some buffering capacity - it takes tap water and buffers it up a couple points (around 8 or so). You'd have to read the packaging to see if it actually has any fertilizing qualities; however, if I remember correctly, it just has a high CEC, meaning it'll hold ferts making it available for plants.

I've never used it in SW, but if Seachem says it's OK, I'd take their word on it - they seem to be very upfront about thier products. If you're at all reticent to use it, give their CS Dept. a call - they have excellent customer support.