feldspar

[dutoits]

is Feldspar safe for use in fishtanks?

[nlribeiro]

Feldspar is the mineral name given to a group of minerals distinguished by the presence of aluminum (Al) and the silica ion (SiO4) in their chemistry.

The presence Aluminium in its composition, by itself poses no problem1, as is not a known ecotoxicity agent, it doesn't hardens the water, nor does it changes the pH, but of couse it might interact with any other chemicals you add to your water (meds, conditioners, ...)

Feldspar, and its variation acounts for almost 50% of earths crust2, it's a component of granite (not advisable in an fresh water aquarium, due to the presence of quartz, hardens the water, and has a proteic inhibitor that ampers the bacterial biofilm in aquarium soil, hence it impairs the nitrogen cycle.

1 - http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35477#Ecotoxicity
2 - http://www.mii.org/Minerals/photofelds.html