Volcanic rock for Filters

[Kingkat]

Has anyone used volcanic rock successfully for biological substrate in trickle filters?
Cheers,
David.

[Merrilyn]

I do know some African Cichlid fans use them in their sumps, but I'm not too sure what it would do to the pH of the water.

I think there are better options.

[Kingkat]

Merrilyn, I can't think of anything else that would be cost effective as I need about 50 lt for the filter. If it was for cichlids I would use coral rubble but this system is for angels, geos, peps etc.
Cheers,
David.

[bitrusty]

hi david i use lava rock with filter wool in all my tanks in a side drop configuration and it has been trouble free for 2 years.i breed geos and other south american cichlids with this method hth russ

[Kingkat]

Cheers Russ and everyone else for their input.