DSB in DT is it possible...?

What are you using as a gravel tidy?

The literature indicates that you can have +5cm of sand above the gravel tidy easily. You want the upper layers disturbed and turned over. It’s just the lower layers that need to be undisturbed and anaerobic. The disturbance of the upper layers is supposed to help prevent everything from going bad. In my new set up my gravel tidy is going to be in the middle of the 10 – 13cm DSB (in the DT). If you have it a little deeper I imagine the fish will prefer it.
Why have the gravel tidy so shallow?


I'm going to be setting up my DSB soon in my DT. DSB will be layered with "gravel tidy" between layers. My top layer will be about 25 -30 mm before exposing the gravel tidy to prevent fish etc burrowing too deeply or undermining rockwork. Also makes it easy to siphon off a small section of this layer to rinse / clean from time to time.
 
Aragonite, I'm told not only buffers but also leaches elements such as storontium into the water. I can't afford aragonite so I stuck a 5cm layer of coral sand at the bottom of the dsb in my sump partly for buffering purposes. It seams to work and different grubs in the sand have their preferances with regards to the grain sizes. You can purchase strontium aditives for less than R1000 000! :)
 
aragonite, I'm told not only buffers but also leaches elements such as storontium into the water

If so, then it also leaches phosphate, nitrate, ...

So Hennie what you are saying Aragonite is no benefit to a tank or dsb

No, all I'm saying is that the benefits don't add up to the cost of the stuff, and it's much easier, and cheaper, to just add whatever "additives" your system really needs by other means.

If the aragonite sand bed was deep enough to result in the bottom portion becoming acidic then it will "leach" out the calcium, carbonate, magnesium, and whatever else was initially absorbed by the living corals which made the aragonite in the first place - but as anyone who has run a calcium reactor would confirm, nothing much happens until the pH drops to around 6.9, and the "leaching" only really gets going at a pH of below 6.7, and that is pretty low.

To further expand the analogy with a calcium reactor, consider the following: My calcium reactor use more than 20kg of medium per year (and many other tanks I know of use considerably more...). If the DSB aragonite reaction is to be meaningful in terms of the amount of "additives" it provides, then the sand bed would decrease in size over only a few years - has anyone actually observed this to happen?

IMHO, rather spend the cost of the aragonite in buying more, or better quality, live rock, or on a proper calcium reactor.

Hennie
 
What are you using as a gravel tidy?

The literature indicates that you can have +5cm of sand above the gravel tidy easily.

Actually, one does not need another complication such as this in a DLSB - it is "old school" and originated with the concept of a plenum sand bed.

Hennie
 
Aragonite is apparently better, it is claimed to have some buffering capabilities,

Unfortunately, this is a very persistent myth in our hobby. Aragonite does not dissolve significantly in salt water... if it did, we'd all be watching our live rock disappear. It might make some negligible contribution to a tank's buffering capacity, but that's all. Now, *maybe*... on a micro-environment level, maybe it helps buffer the very immediate environment of the sand grains... but I don't know. As far as I can tell, silica sand DSBs can home just as much life.

FWIW, I've had sand beds of silica sand that at least appeared to be just as functional and alive as any aragonite sand bed... and I never had any alkalinity or pH issues with it.
 
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