Andrew Butler
Member
I realise that, I think it is amongst his most published phrases on here - that's why I commented.
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Is lava rock safe for use under the substrate?
AverageWhiteBloke
Member
I think there maybe some benefit in fish only systems would be my take on it. We are dealing with things here on the microscopic level, the friendly bacteria just want something to cling to so in a planted aquarium the optimum medium to use would be something with maximum surface area which causes the least drag, poor flow is the no1 issue and the surface area secondary to that. Hopefully most people clean out their filters quite often and a fair amount of bacteria are lost during that process which quickly build back up anyway in an established tank. Realistically it's the plants we want to do the filtering job as they are much better at it than the canister filter and they would rather have the flow.
In a fish only system, I would guess sintered glass, lava rock and all the very porous type medium would have a lot of anaerobic dead spots internally as the oxygenated water only passes over the surface, the inside will fill with anaerobic bacteria which could be quite effective at stripping out nitrate over time but as we are not in the business of stripping out nitrogen, in fact adding extra, you have to look at what would be the best in a filter regarding water passing through it. Obviously its going to be a lot easier for water to make its way through loads of scrubbies with lots of routes through than a load of rocks with limited paths the water can take.
As a bulking up medium lava rock is perfect as its inert, bulky and has some nutrient absorption qualities and wouldn't look out of place if it popped up out the gravel when it settles. My only suggestion there would be that plant roots can't make their way through it as say a mesh bag of cheap gravel. The only downside to the bag of gravel would be you either have to go in a shop to buy a pair of tights or worse ask the OH to get some or explain why you want a pair of her old ones. That's going to take some explaining
Lava rock is also better in a sump than a canister I would guess as it has the option of passing over it if on the bottom rather than make its way through it.
Just my thoughts on it, they could be all wrong though, I usually am. I'm just thinking I don't think it advantageous to spend $$$$$$$ on the latest nutter bstard canister filter then choke it up with a load of stones drastically reducing the flow through it.
In a fish only system, I would guess sintered glass, lava rock and all the very porous type medium would have a lot of anaerobic dead spots internally as the oxygenated water only passes over the surface, the inside will fill with anaerobic bacteria which could be quite effective at stripping out nitrate over time but as we are not in the business of stripping out nitrogen, in fact adding extra, you have to look at what would be the best in a filter regarding water passing through it. Obviously its going to be a lot easier for water to make its way through loads of scrubbies with lots of routes through than a load of rocks with limited paths the water can take.
As a bulking up medium lava rock is perfect as its inert, bulky and has some nutrient absorption qualities and wouldn't look out of place if it popped up out the gravel when it settles. My only suggestion there would be that plant roots can't make their way through it as say a mesh bag of cheap gravel. The only downside to the bag of gravel would be you either have to go in a shop to buy a pair of tights or worse ask the OH to get some or explain why you want a pair of her old ones. That's going to take some explaining
Lava rock is also better in a sump than a canister I would guess as it has the option of passing over it if on the bottom rather than make its way through it.
Just my thoughts on it, they could be all wrong though, I usually am. I'm just thinking I don't think it advantageous to spend $$$$$$$ on the latest nutter bstard canister filter then choke it up with a load of stones drastically reducing the flow through it.
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