I'm planning on upgrading my 90g BB tank to a bigger 180g-250g tank and want to go back to a DSB setup. I'm wanting to know what size sand those of you with high flow sps and DSB setups are using. Also, I want about 4-5" depth and am wondering if using crushed coral on the very bottom layer of sand would be ok? Would that help with the anerobic condition?
High Flow and DSB????
- Thread starter sjj80
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MCsaxmaster
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Nope, crushed coral is the worst of all conceivable worlds. Sediments of that grade collect in areas subject to frequent, strong flushing. There's no way to easily replicate the kind of water flow we're talking about here in an aquarium (without an outboard motor that is...and I'm not exaggerating 
). Detritus doesn't collect or get processed to any significant degree in sediments like that because there is just too much disturbance and flushing. Siphoning out the gravel every few days might be a way to replicate it, but it would be awefully labor intensive for little benefit.
For most aquaria, just sugar-fine sand is fine. You can have what most folks would consider pretty strong water flow without problems (easily 6 in/s). For tanks with really strong circulation (though still pretty modest compared to what we see in nature) one might need to add a thin layer of larger grade aragonite (say 1-2 mm size) to the surface.
). Detritus doesn't collect or get processed to any significant degree in sediments like that because there is just too much disturbance and flushing. Siphoning out the gravel every few days might be a way to replicate it, but it would be awefully labor intensive for little benefit.For most aquaria, just sugar-fine sand is fine. You can have what most folks would consider pretty strong water flow without problems (easily 6 in/s). For tanks with really strong circulation (though still pretty modest compared to what we see in nature) one might need to add a thin layer of larger grade aragonite (say 1-2 mm size) to the surface.
werdlone
New member
I would recommend "seaflor special grade" carib sea substrate. It is 1-1.7mm grain size. I think it is the largest substrate that will give you the DSB benefits. Crushed coral is a detritus trap. I had a little sand shifting with my 2 tunze 6100's in a 150gal tank, but with the right angle and tuned down on my controller it is working well. I would recommmend a shallow sand bed in the display and a remote DSB with sugar fine substrate around 6" depth or more. Just my 2cents.
OnlyCrimson
New member
I think some sort of oolitic sand with a layer of aragonite on top would work well.
MCsaxmaster
New member
Huh-uh--by "flushing" I mean that the wave action, tidal flow and storm-induced flow is so strong that it washes everything smaller than gravel away. Hence, detritus is not processed in these areas--it is flushed elsewhere and processed elsewhere. We can't readily provide this kind of water flow in aquaria. Thus, detritus will buildup in the sediments, but the large grain size will prevent efficient processing. You'll end up with a significant source of nitrate and phosphate, which is not the goal, instead of a source of plankton and pseudoplankton, which is the goal.
Crushed coral has no place in a deep sand bed. If it's placed on the bottom, it will eventually work its way to the top anyway. But, why would you want to put down a layer of crushed coral at all?
Chris
I was just wondering if it would provide more anerobic area to help reduce nitrate since that's another function of a DSB, but I guess if it would make it's way to the top of a 5" DSB then it's not a good idea. I def. don't want detritus buildup and I surely wouldn't use crushed coral on the top layer for that reason.
I mainly want the sand so I'm not limited as to what fish and cuc I can have like I am now with my BB setup. I'm also planning on doing a closed loop and will have a couple outlets pointing up from out of the sand to help keep detritus from settling in the sand.
I mainly want the sand so I'm not limited as to what fish and cuc I can have like I am now with my BB setup. I'm also planning on doing a closed loop and will have a couple outlets pointing up from out of the sand to help keep detritus from settling in the sand.
MCsaxmaster
New member
Crushed coral would significantly reduce the potential for denitrification--I wouldn't use it at all, and in fact I wouldn't use it in most aquaria.
You want appropriate water flow, but with appropriate water flow you'll have appropriate processing of detritus in the sandbed. There's no way to prevent the transport of detritus to the sandbed, and in fact that is exactly what we want
With appropriate flow and infauna the sandbed will take in detritus, process it, and pump out plankton and pseudoplankton. That will in turn be eaten by the critters in the tank (e.g., corals) or skimmed out.
MCsaxmaster
New member
I'd use sugar-sized sand. You can cover this with a thin (< 1/4") layer of slightly larger grade sand (1-2 mm) if you like and you should have a perfectly functional sandbed.
MCsaxmaster
New member
:thumbsup:
