keith burn
Active Member
Hi,
I have read a lot on saltwater (sw) tanks and sw fishkeeping in the past 5 years;
What type of sandbed is a question that comes up from time to time
so I'd like to put the question to bed, lol.
The stuff at the bottom of the tank...
1) glass bottom or no sand ( bare bottom )
(imo not a good look) But...
You want to be able to remove the waste from the tank.
With good circulation to help things get stirred up detritus will stay in the water column
and be filtered out by your filter system. Detritus that builds up behind the live rock can be siphoned out.
If You find dead spots, you can add flow or move the existing flow and in time, you will not have them.
No detritus in the tank will help keep water lvl's in balance.
You could use bare bottom in the display tank (DT) but nothing is to say you cannot have a sandbed in the sump and have the best of both worlds.
Most wet/dry filters that are used as sumps these days have a
middle section that will work well for a deep sand bed (DSB).
This IMO is the best way to get the bio benefit without the look of a sandbed in the DT.
A skimmer is a must IMO and if one is used, it needs to be put before the
DSB so the beneficial food will go into the tank and not in its cup.
Bare bottoms will not be bare forever. With time and exposure to lights, it will get covered with coralline and all kinds of stuff as your L/R matures,if you do not clean it like the front glass.
This will make the bottom look more like what you see on the L/R but it will take time for it to cover the bottom.
With a mature tank the bottom is a bio filter like the L/R and as it grows it may make up for the lack of biological filter of a sandbed.
This came from a big test on substrates...
(We did not test bare bottom tanks, but the data clearly suggest that the shallower the sediment, the higher the mortality rate, and you can't get much shallower than a bare bottom tank!)
Sand is the most popular substrate but in different particle sizes.
(fine sand 0.2mm) This is what most call (sugar sand or fine sand). It is good for looks and it will not hold detritus in it. You must manage the flow not to hit it or you will have a snow storm in the tank; not good for the look or the L/R. You cannot siphon it to clean it but, this is one of the thing I love, you have sand sifters clean it.
(coarse 2.0mm) This is CRUSHED CORAL, not the best way to go Imo it holds detritus. Phosphates ended up significantly higher in tanks with coarse sediments.Most sand dwellers can and will get cut by it. Sand sifters do not work well in it, unfortunately.It is not all bad, it is a good way to get help with calcium in to the tank(long term). It helps keep fine sand from getting hard and keep the flow going through it.
Imo a mix of fine and coarse sand 4-to-1 fine to coarse is best.
2) Sandbed 1 in to 3 in deep.
Biological Filtration
The basic principle with biological filtration is to take waste particles and break them down safely by biological means.
Regardless of how you explain or define it, the idea is to use living organisms to break down and consume waste products. Sandbeds are currently the most popular form of filtration media in today’s aquariums. They give you the ability to have sand sifting fish and some inverts that sift as well.
Live rock in fish only tanks may not provide enough living area for sufficient bacteria to keep all the nitrates out of your water. Sand helps with a place for the organisms to breed and live in significant quantities. The biological organisms will help if you have die off or a fish that has died; less material to be converted into ammonia.
It will give a base to set your L/R on and not the glass.
3) deep sandbed 3 in to 6 in deep
Biological Filtration And Anaerobic Filtration
The basic principle with Anaerobic Filtration is that it does not require air or oxygen for life applied especially to those microbes to which free oxygen is unnecessary.
All the Biological of a sandbed and more.
First) the deeper regions of the sandbed provide a great anaerobic environment for denitrifying bacteria.
Second) sandbeds are home to numerous meiofauna which will nthusiastically devour any uneaten food or waste material that falls from above.
Every bit that they consume is a little less material to be converted directly into ammonia.
(Biodiversity)A reef's success is the wide range of organisms that keep the system in balance.Balance is the key,if one lvl is off, a deep sandbed can compensate and bring it back to a balance.
The DSB will provide a food supply for fish and all kinds of critters in your tank.In time a breeding ground for food and organisms will help the system stay in balance.
I have read a lot on saltwater (sw) tanks and sw fishkeeping in the past 5 years;
What type of sandbed is a question that comes up from time to time
so I'd like to put the question to bed, lol.
The stuff at the bottom of the tank...
1) glass bottom or no sand ( bare bottom )
(imo not a good look) But...
You want to be able to remove the waste from the tank.
With good circulation to help things get stirred up detritus will stay in the water column
and be filtered out by your filter system. Detritus that builds up behind the live rock can be siphoned out.
If You find dead spots, you can add flow or move the existing flow and in time, you will not have them.
No detritus in the tank will help keep water lvl's in balance.
You could use bare bottom in the display tank (DT) but nothing is to say you cannot have a sandbed in the sump and have the best of both worlds.
Most wet/dry filters that are used as sumps these days have a
middle section that will work well for a deep sand bed (DSB).
This IMO is the best way to get the bio benefit without the look of a sandbed in the DT.
A skimmer is a must IMO and if one is used, it needs to be put before the
DSB so the beneficial food will go into the tank and not in its cup.
Bare bottoms will not be bare forever. With time and exposure to lights, it will get covered with coralline and all kinds of stuff as your L/R matures,if you do not clean it like the front glass.
This will make the bottom look more like what you see on the L/R but it will take time for it to cover the bottom.
With a mature tank the bottom is a bio filter like the L/R and as it grows it may make up for the lack of biological filter of a sandbed.
This came from a big test on substrates...
(We did not test bare bottom tanks, but the data clearly suggest that the shallower the sediment, the higher the mortality rate, and you can't get much shallower than a bare bottom tank!)
Sand is the most popular substrate but in different particle sizes.
(fine sand 0.2mm) This is what most call (sugar sand or fine sand). It is good for looks and it will not hold detritus in it. You must manage the flow not to hit it or you will have a snow storm in the tank; not good for the look or the L/R. You cannot siphon it to clean it but, this is one of the thing I love, you have sand sifters clean it.
(coarse 2.0mm) This is CRUSHED CORAL, not the best way to go Imo it holds detritus. Phosphates ended up significantly higher in tanks with coarse sediments.Most sand dwellers can and will get cut by it. Sand sifters do not work well in it, unfortunately.It is not all bad, it is a good way to get help with calcium in to the tank(long term). It helps keep fine sand from getting hard and keep the flow going through it.
Imo a mix of fine and coarse sand 4-to-1 fine to coarse is best.
2) Sandbed 1 in to 3 in deep.
Biological Filtration
The basic principle with biological filtration is to take waste particles and break them down safely by biological means.
Regardless of how you explain or define it, the idea is to use living organisms to break down and consume waste products. Sandbeds are currently the most popular form of filtration media in today’s aquariums. They give you the ability to have sand sifting fish and some inverts that sift as well.
Live rock in fish only tanks may not provide enough living area for sufficient bacteria to keep all the nitrates out of your water. Sand helps with a place for the organisms to breed and live in significant quantities. The biological organisms will help if you have die off or a fish that has died; less material to be converted into ammonia.
It will give a base to set your L/R on and not the glass.
3) deep sandbed 3 in to 6 in deep
Biological Filtration And Anaerobic Filtration
The basic principle with Anaerobic Filtration is that it does not require air or oxygen for life applied especially to those microbes to which free oxygen is unnecessary.
All the Biological of a sandbed and more.
First) the deeper regions of the sandbed provide a great anaerobic environment for denitrifying bacteria.
Second) sandbeds are home to numerous meiofauna which will nthusiastically devour any uneaten food or waste material that falls from above.
Every bit that they consume is a little less material to be converted directly into ammonia.
(Biodiversity)A reef's success is the wide range of organisms that keep the system in balance.Balance is the key,if one lvl is off, a deep sandbed can compensate and bring it back to a balance.
The DSB will provide a food supply for fish and all kinds of critters in your tank.In time a breeding ground for food and organisms will help the system stay in balance.
