Darrell Quadling Posted October 7, 2007 Report Share Posted October 7, 2007 Has anyone ever used scoria as a bio filter medium ?? I feel it should work as it has zillions of voids and is cheap as . darrell Quote Link to comment Share on other sites More sharing options...
Warren Posted October 7, 2007 Report Share Posted October 7, 2007 Yes it works well. However, and it's big HOWEVER, you have to clean it very well before putting it in your filter. Scoria is made when toxic gases turn rock into a cheesle type substance. As such there are all sorts of nasties in it. This is what I did to make it safer (not sure if it's required but I wasn't taking any risks with my fish!) I acid etched it for a week, first with sulphuric and then with hydrochloric. Both are VERY dangerous acids and need to be handled properly and disposed of properly. If you are unsure then don't use it. Once thoroughly rinsed and a pH test shows no change then it's ready to go. Smashed pumice works about the same and is a lot safer to use if collected from the beach where it's already been well rinsed by the river that took it there. Only problem with pumice is silicates... Quote Link to comment Share on other sites More sharing options...
Darrell Quadling Posted October 7, 2007 Author Report Share Posted October 7, 2007 Thanks for that, by the time one takes the cost of acid and the hazards into account there is little point..again thanks..darrell Quote Link to comment Share on other sites More sharing options...
David R Posted October 7, 2007 Report Share Posted October 7, 2007 This is what I did to make it safer (not sure if it's required but I wasn't taking any risks with my fish!) I acid etched it for a week, first with sulphuric and then with hydrochloric. Both are VERY dangerous acids and need to be handled properly and disposed of properly. If you are unsure then don't use it. Once thoroughly rinsed and a pH test shows no change then it's ready to go. If you didn't do this would the scoria make the water very acidic?? Quote Link to comment Share on other sites More sharing options...
herefishiefishie Posted October 7, 2007 Report Share Posted October 7, 2007 David, read this part of the quote you used again.... Once thoroughly rinsed and a pH test shows no change then it's ready to go. Frenchy Quote Link to comment Share on other sites More sharing options...
Robert Smith Posted October 8, 2007 Report Share Posted October 8, 2007 The danger of pumices, scoria and the like is that the nasties leach out slowly over time. Pumice that has been floating around for hundreds or thousands of years may be well leached, but how do you know? Even acid washing will have little effect. The nasties are in the sealed gas pockets. The fact that they are sealed makes them unwashable. They slowly permeate through the rock over time. The upside is that fish don't usually live long enough for this to be a concern. But to be safe I'd leave the pumice/scoria under water for a month before using. I think the acid wash is overkill. Quote Link to comment Share on other sites More sharing options...
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