Using freshwater planted substrates in Saltwater tanks?

[vonjankmon]

Thinking of setting up a seagrass tank and I was trying to ensure proper nutrients for the grasses. I have and have had several planted freshwater tanks and used all kinds of different planted substrates with success but was wondering if it would be safe to do a layer of a substrate designed for freshwater planted tanks near the bottom of the DSB for the seagrass tank. The DSB would be about 5 inches or so for the seagrass.

Was looking at the Seachem planted substrates as they are sold dry so I would not have to worry about the die off of from some of the live freshwater substrates.

Anyone have experience with this? One concern I do have is the listed copper content some of the planted substrates have.For instance the mineral information for Onyx Sand by Seachem is below, amounts are in PPM.

Aluminum 822
Barium 5
Calcium 197500
Cobalt 4
Chromium 10
Copper 4
Iron 2846
Potassium 417
Magnesium 115400
Manganese 43
Sodium 135
Nickel 7
Vanadium8
Zinc 23

Experiences with this type of thing are very welcome but informed opinions are too.

 

[ccCapt]

I have no experience with the stuff, but there is no way I would even put that near my tank just looking at the list of stuff in it.

Aluminum - 822ppm: Natural Sea Water is 0.00014-0.001 ppm and high aluminum is know to be a coral irritant.
Zinc - 23 ppm: NSW is 0.000003-0.0006 ppm and is as lethal, if not more, as copper.

 

[yote]

+1 Capt.
I think you'd be better off with something like refugium mud.I'd think that the needs of seagrasses would be totally different than freshwater plants any how.