DSB versus no substrate
- Thread starter daisy
- Start date
robchuck
Active Member
Both options have their benefits, and you just have to weigh the pros and cons of each.
I do believe that DSBs work wonders at denitrification, but unfortunately for me, I have had more problems than success with a DSB. So I will go with a shallow sand bed or a cutting board bottom for my next tank. I never had nuisance algae problems in any of my tanks until I added a DSB. In all fairness though, I attributed the algae problems to improper stocking of the DSB on my part. All the LR, live sand, and detrivore kits I have added have slowed down the growth of nuisance algae.
Hearing and reading several stories lately of DSBs crashing in established tanks has scared me out of putting a DSB in the tank I'll be starting this summer. One theory (and the one I happen to go along with) is that the DSB becomes a nutrient sink, where it soaks up nutrients until the point of saturation, when it releases them back into the tank.
To answer your pod question, by going with a shallow sandbed for decoration purposes, cuttingboard or Starboard bottom, or barebottom, you would be reducing the amount of microfauna in your tank and therefore would have less pods.
If you like the idea and the benefits of a DSB, but are uncertain about putting one in your display tank, you could do what I am contemplating on my next system and add one remotely in a refugium. Plumbing your system this way would allow you to take the 'fuge offline (by closing a few ball valves) to allow for proper maintenance of the DSB while not effecting the display.
I do believe that DSBs work wonders at denitrification, but unfortunately for me, I have had more problems than success with a DSB. So I will go with a shallow sand bed or a cutting board bottom for my next tank. I never had nuisance algae problems in any of my tanks until I added a DSB. In all fairness though, I attributed the algae problems to improper stocking of the DSB on my part. All the LR, live sand, and detrivore kits I have added have slowed down the growth of nuisance algae.
Hearing and reading several stories lately of DSBs crashing in established tanks has scared me out of putting a DSB in the tank I'll be starting this summer. One theory (and the one I happen to go along with) is that the DSB becomes a nutrient sink, where it soaks up nutrients until the point of saturation, when it releases them back into the tank.
To answer your pod question, by going with a shallow sandbed for decoration purposes, cuttingboard or Starboard bottom, or barebottom, you would be reducing the amount of microfauna in your tank and therefore would have less pods.
If you like the idea and the benefits of a DSB, but are uncertain about putting one in your display tank, you could do what I am contemplating on my next system and add one remotely in a refugium. Plumbing your system this way would allow you to take the 'fuge offline (by closing a few ball valves) to allow for proper maintenance of the DSB while not effecting the display.
razoreqx
Active Member
Thats what I have also done.
And I have a small cosmetic layer of CC in the display tank..
But ive been testing this out in my fuge.....
In the refugium im running a 6" DSB. Under the DSB I have installed a PVC pipe with holes in it the length of the sand bed. When I do my water changes I turn off the pumps and connect a pump to the PVC under the Sandbed in the refugium and pump water out of the tank from the bottom of the refugium.
I'll keep you posted on the results ..
And I have a small cosmetic layer of CC in the display tank..
But ive been testing this out in my fuge.....
In the refugium im running a 6" DSB. Under the DSB I have installed a PVC pipe with holes in it the length of the sand bed. When I do my water changes I turn off the pumps and connect a pump to the PVC under the Sandbed in the refugium and pump water out of the tank from the bottom of the refugium.
I'll keep you posted on the results ..
blk822
Member
I had a semi deep cc bed and after a few years I just decieded the other day to vac. it to see what was in it.And man it was nasty,semelled really bad too. So I removed it and added aragamaxx sand by caribsea. It supposed to contain cal. and a hole bunch of stuff to help with trace elements and ph balance, and a bunch of other things. After removing the cc bottom my phos. went from .25ppm to .01 ppm in a few days . And all the hair algae on my rock is dieing off. So if you go with a bed I would use a aragonite sand, do a seach on it and check out the stuff. Pretty cheap to.
leboeuf
Member
I can't speak on DSB due to the fact I never gave it a shot. I think it is a much more natural look but could have long term negative effects. I can however compare CC with bare bottom. CC was always dirty, except for the first month when it look incredible. Always having diatom outbreaks with algae issues. Took four water changes to syphon out all the CC and go with Barebottom. At first it looked like crap. However, I sent four 1200 gph powerheads directly into the bottom glass and within a month had enough coraline growth to cover the bottom glass. It is now a carpet of purple coraline and easy as hell to maintain. I have the PH positioned to send all detritus to the back of the tank which I can syphon out once a month during changes. Hope this helps.
I plan to try the DSB one day. Cant beat the look of mother nature!
I plan to try the DSB one day. Cant beat the look of mother nature!
razoreqx
Active Member
This was posted on anothe forum but I'll share it here as I have always been leary of DSB's but I have been testing the example listed below.
.....
I know the DSB followers will say come back in 5 years when you have proven it works. My response is it does not take years to prove positive results and the system can at any time be made into a Jauberet of DSB by simply not using it, so there is no risk in using it. I also believe for newly established systems, that are set up with CPW, reef keepers will have a much greater chance of long term success.
CPW is based on and assumes the DSB and the Jauberet systems do not work well as biological filters. That is not to say oxic and anoxic biological filtration is not taking place in them, but that it is just terribly inefficient and uncontrolled biological filtration. It assumes at best you can walk a tight rope using them, and make them appear to be functioning, only to have a disaster a few months or years into their operation. If these systems are kept biologically very lightly loaded they may appear to be functioning, when they in fact may be doing more harm than good by slowly or abruptly allowing uncontrolled anoxic septic fluid to flow back into the system or deal with a potential death bomb if you stir up the bed.
If the above is true, why should I not simply use a BB (bare bottom)? The more biological useable and functioning biological surface area you have in a tank the better. It helps to keep the tank stable from the increased biological loading when sudden death or overfeeding occur. It is the same reason the use of live rock has been so successful in making reef tanks possible.
CPW (Controlled Plenum Wasting)
1. It assumes the fluids in the bottom of a DSB are anoxic and are not fully stabilized.
2. It assumes anoxic waste can buildup at a faster rate than the available bed active biological surface can fully stabilize it.
3. It is designed to remove unprocessed or reconstituted nitrates, nitrites, ammonia, phospahtes and other organic waste that accumulates in the bottom of the bed.
4.It assumes DSB and Jauberet designs are not 100% effective in biological stabilization, and infact do cause a major build up of anoxic Hydrogen Sulfide in the bed that does and can leak back into the tank.
5. It is simply a method to compensate for this inefficiency.
6. It improves the DSB biological efficiency by moving fresh food into the zones.
First I will address a major DSB and Jauberet process fallacy often stated.
1.) Anaerobic processing is completely stopped if anoxic fluid( partially oxygenated) moves into a DSB zone and it takes weeks to recover. All of the waste I remove does not show that to be factual.
You do not need or want large low or no flux dead zones in a DSB. You want a positive low transport rate of fresh septic material into and out of these zones. Depending completely on critters in a bed to do this is foolish. Most critters do not like to go into the large anoxic sulfide laden zones that quickly build up.
What is CPW (Controlled Plenum Wasting)? I will given a concise description of how I built my system and how it works. It is not very complex or should it be highly controversial, except for the fact that it may be viewed a heresy by advocates of DSB's. It is really based on common sense. It simply keeps a more positive flow into the bed and not back out into the tank water column.
In my system I have installed a plenum piping system, at the bottom of the bed, with relatively low very small number of orifices. I do use a coarse uniform agronite crushed coral as a DSB media (Carib Sea Special Grade Sand). This is all to assure of a more even flow distribution across the bed. A conventional commercial bottom filter, with is large open area, can and will rapidly short circuit the flow.
On a daily basis I drain the plenum of a couple of pints of anoxic waste that accumulated.
That is all there is to the system.........
I have the drain valve controlled with an X10 switch and my computer. It drains out a small amount every 8 hours.
Set up- Reef Tank: 45g half barrel, 30Hx15Dx30W, 5" DSB with a plenum bottom filter from which I drain 1 couple of pints of waste daily, Carib Sea Special Grade Sand 40 lb, 40Lbs Fuji branch LR, 15 G BB Fuge, Kalk Reactor, Skimmer, Ozone feed.
Why do I say this approach works better than other approaches that try to neutralize all the waste within the bed. It is based on very obvious measured results over two months.
1. What is drained out is always anoxic and has a rotten egg smell. Not something you want to remain in the tank. The fluid drained is anoxic, pH of the wasted fluid is always .5 lower than the water column, three to four times high ALK readings in the wasted fluid; all of which are an indication of continuous biological sulfide processing taking place deep in the bed.
2. When I have purposely allowed even a small amount to this anoxic sulfide laden fluid to re-enter the tank, the tank ORP read out drops like a rock and takes nearly a half day to recover. Even with the addition of ozone into the skimmer.
3. I have stopped making weekly 25% water changes.
4. My ORP readings have never been higher, they are approaching 400 mv. . Infact they remain above the ORP 350 mv set point for ozone feed and are continuing to increase. Little to no ozone is now even being added to the skimmer.
5. My water quality continues to improve, and all of the coral are responding positively to the water quality.
Is the above proof positive that this approach has merit? It does for me. Sure I will continue to monitor and tweek the wasting rate to see if I can improve upon the result. I am sure other will improve upon this approach and I will continue to monitor and post the good and bad.
I have experienced no negatives. My tank is very stabile with very low ORP swings and much more rapid recovery. I no longer do weekly water changes, which was a pain in the butt. The total amount of water removed is a small fraction of that need during normal water changes.
Some of the other potential but unproven positives.
http://www.ozestuaries.org/indicato..._reduction.html
Organic matter decomposition can be a consequence of sulfate reduction in the sediments of coastal waterways (and other aquatic systems) [1]. The process is performed by anerobic sulfate-reducing bacteria. The bacteria require: metabolisable organic matter ; an anoxic environment (or microenvironment); and dissolved sulfate. Hydrogen sulfide gas (H 2S) and alkalinity are generated in the process (see simplified reaction 1).
Consequences of Sulfate Reduction
H2S smells like rotten eggs, and can detract from the aesthetic amenity of coastal waterways when it is released to the atmosphere [2,5].
H2S is toxic to a wide range of aquatic organisms [3];
H2S can inhibit nitrification [4]. When nitrification is inhibited, coupled
nitrification-denitrification is also inhibited.
Ammonium (NH 4+) is released from organic matter during degradation by
sulfate reduction (Equation 3) [6]. Ammonium is a bioavailable and is
readily taken up by plants.
(Eq. 3) 106(CH 2O)16(NH 3)(H 3PO 4) + 53SO 42- “106 CO 2+ 16 NH 3+ H 3PO 4+
106 H 2O + 53 S 2- Iron sulfides ( e.g . pyrite), formed during sulfate
reduction, are an active component of acid sulfate soils (***),
and problems with acid production and drainage can arise if the pyrite
is oxidised .
Iron sulfides cannot bind phosphate . Therefore, when iron oxyhydroxides are converted to iron sulfides during sulfate reduction, phosphate can be released to the water column [9].
______________________________________________________________
The above leaves little doubt in my mind as to why a conventional DSB is a crap shoot and a ticking bomb. I will continue to run my experiment with removing this sulfide rich waste soup to see if a DSB can be made to work. Without a method of removing all of this bad soup from the bottom of any DSB I don't believe they can* work. *(can is relative. I mean eventually fail)
I personally believe your odds at the crap table in Vegas are better than you odds of having a reef tank using a DSB more than a few years before it flips or leaks back into the tank killing everything. If you had a strictly SPS tank with few fish you may beable to stretch the tank life out a few more years.
Phosphate non-binding can be a problem with a DSB, but the biggest advantage of a BB, and only using live rock, is that you have very little sulfate reduction zone to cause an upset. The negative is you have greatly reduced biological processing surface.
With a BB don't have a big hot cauldron of anoxic sufide soup that a DSB can produce. It is loaded with ammonia, nitrates, is nitrification inhibiting , toxic H2S laden, and an oxygen depleting soup building up in a DSB waiting to boil over and snuff out life.
.....
I know the DSB followers will say come back in 5 years when you have proven it works. My response is it does not take years to prove positive results and the system can at any time be made into a Jauberet of DSB by simply not using it, so there is no risk in using it. I also believe for newly established systems, that are set up with CPW, reef keepers will have a much greater chance of long term success.
CPW is based on and assumes the DSB and the Jauberet systems do not work well as biological filters. That is not to say oxic and anoxic biological filtration is not taking place in them, but that it is just terribly inefficient and uncontrolled biological filtration. It assumes at best you can walk a tight rope using them, and make them appear to be functioning, only to have a disaster a few months or years into their operation. If these systems are kept biologically very lightly loaded they may appear to be functioning, when they in fact may be doing more harm than good by slowly or abruptly allowing uncontrolled anoxic septic fluid to flow back into the system or deal with a potential death bomb if you stir up the bed.
If the above is true, why should I not simply use a BB (bare bottom)? The more biological useable and functioning biological surface area you have in a tank the better. It helps to keep the tank stable from the increased biological loading when sudden death or overfeeding occur. It is the same reason the use of live rock has been so successful in making reef tanks possible.
CPW (Controlled Plenum Wasting)
1. It assumes the fluids in the bottom of a DSB are anoxic and are not fully stabilized.
2. It assumes anoxic waste can buildup at a faster rate than the available bed active biological surface can fully stabilize it.
3. It is designed to remove unprocessed or reconstituted nitrates, nitrites, ammonia, phospahtes and other organic waste that accumulates in the bottom of the bed.
4.It assumes DSB and Jauberet designs are not 100% effective in biological stabilization, and infact do cause a major build up of anoxic Hydrogen Sulfide in the bed that does and can leak back into the tank.
5. It is simply a method to compensate for this inefficiency.
6. It improves the DSB biological efficiency by moving fresh food into the zones.
First I will address a major DSB and Jauberet process fallacy often stated.
1.) Anaerobic processing is completely stopped if anoxic fluid( partially oxygenated) moves into a DSB zone and it takes weeks to recover. All of the waste I remove does not show that to be factual.
You do not need or want large low or no flux dead zones in a DSB. You want a positive low transport rate of fresh septic material into and out of these zones. Depending completely on critters in a bed to do this is foolish. Most critters do not like to go into the large anoxic sulfide laden zones that quickly build up.
What is CPW (Controlled Plenum Wasting)? I will given a concise description of how I built my system and how it works. It is not very complex or should it be highly controversial, except for the fact that it may be viewed a heresy by advocates of DSB's. It is really based on common sense. It simply keeps a more positive flow into the bed and not back out into the tank water column.
In my system I have installed a plenum piping system, at the bottom of the bed, with relatively low very small number of orifices. I do use a coarse uniform agronite crushed coral as a DSB media (Carib Sea Special Grade Sand). This is all to assure of a more even flow distribution across the bed. A conventional commercial bottom filter, with is large open area, can and will rapidly short circuit the flow.
On a daily basis I drain the plenum of a couple of pints of anoxic waste that accumulated.
That is all there is to the system.........
I have the drain valve controlled with an X10 switch and my computer. It drains out a small amount every 8 hours.
Set up- Reef Tank: 45g half barrel, 30Hx15Dx30W, 5" DSB with a plenum bottom filter from which I drain 1 couple of pints of waste daily, Carib Sea Special Grade Sand 40 lb, 40Lbs Fuji branch LR, 15 G BB Fuge, Kalk Reactor, Skimmer, Ozone feed.
Why do I say this approach works better than other approaches that try to neutralize all the waste within the bed. It is based on very obvious measured results over two months.
1. What is drained out is always anoxic and has a rotten egg smell. Not something you want to remain in the tank. The fluid drained is anoxic, pH of the wasted fluid is always .5 lower than the water column, three to four times high ALK readings in the wasted fluid; all of which are an indication of continuous biological sulfide processing taking place deep in the bed.
2. When I have purposely allowed even a small amount to this anoxic sulfide laden fluid to re-enter the tank, the tank ORP read out drops like a rock and takes nearly a half day to recover. Even with the addition of ozone into the skimmer.
3. I have stopped making weekly 25% water changes.
4. My ORP readings have never been higher, they are approaching 400 mv. . Infact they remain above the ORP 350 mv set point for ozone feed and are continuing to increase. Little to no ozone is now even being added to the skimmer.
5. My water quality continues to improve, and all of the coral are responding positively to the water quality.
Is the above proof positive that this approach has merit? It does for me. Sure I will continue to monitor and tweek the wasting rate to see if I can improve upon the result. I am sure other will improve upon this approach and I will continue to monitor and post the good and bad.
I have experienced no negatives. My tank is very stabile with very low ORP swings and much more rapid recovery. I no longer do weekly water changes, which was a pain in the butt. The total amount of water removed is a small fraction of that need during normal water changes.
Some of the other potential but unproven positives.
http://www.ozestuaries.org/indicato..._reduction.html
Organic matter decomposition can be a consequence of sulfate reduction in the sediments of coastal waterways (and other aquatic systems) [1]. The process is performed by anerobic sulfate-reducing bacteria. The bacteria require: metabolisable organic matter ; an anoxic environment (or microenvironment); and dissolved sulfate. Hydrogen sulfide gas (H 2S) and alkalinity are generated in the process (see simplified reaction 1).
Consequences of Sulfate Reduction
H2S smells like rotten eggs, and can detract from the aesthetic amenity of coastal waterways when it is released to the atmosphere [2,5].
H2S is toxic to a wide range of aquatic organisms [3];
H2S can inhibit nitrification [4]. When nitrification is inhibited, coupled
nitrification-denitrification is also inhibited.
Ammonium (NH 4+) is released from organic matter during degradation by
sulfate reduction (Equation 3) [6]. Ammonium is a bioavailable and is
readily taken up by plants.
(Eq. 3) 106(CH 2O)16(NH 3)(H 3PO 4) + 53SO 42- “106 CO 2+ 16 NH 3+ H 3PO 4+
106 H 2O + 53 S 2- Iron sulfides ( e.g . pyrite), formed during sulfate
reduction, are an active component of acid sulfate soils (***),
and problems with acid production and drainage can arise if the pyrite
is oxidised .
Iron sulfides cannot bind phosphate . Therefore, when iron oxyhydroxides are converted to iron sulfides during sulfate reduction, phosphate can be released to the water column [9].
______________________________________________________________
The above leaves little doubt in my mind as to why a conventional DSB is a crap shoot and a ticking bomb. I will continue to run my experiment with removing this sulfide rich waste soup to see if a DSB can be made to work. Without a method of removing all of this bad soup from the bottom of any DSB I don't believe they can* work. *(can is relative. I mean eventually fail)
I personally believe your odds at the crap table in Vegas are better than you odds of having a reef tank using a DSB more than a few years before it flips or leaks back into the tank killing everything. If you had a strictly SPS tank with few fish you may beable to stretch the tank life out a few more years.
Phosphate non-binding can be a problem with a DSB, but the biggest advantage of a BB, and only using live rock, is that you have very little sulfate reduction zone to cause an upset. The negative is you have greatly reduced biological processing surface.
With a BB don't have a big hot cauldron of anoxic sufide soup that a DSB can produce. It is loaded with ammonia, nitrates, is nitrification inhibiting , toxic H2S laden, and an oxygen depleting soup building up in a DSB waiting to boil over and snuff out life.
beachbumtx
Member
Originally posted by RobChuck
Hearing and reading several stories lately of DSBs crashing in established tanks has scared me out of putting a DSB in the tank I'll be starting this summer. One theory (and the one I happen to go along with) is that the DSB becomes a nutrient sink, where it soaks up nutrients until the point of saturation, when it releases them back into the tank.
If it gathers nutrients over time, then it only makes sense to gravel wash (vacuum) the substrate.
I run a 3" deep layer of aragonite snad and vacuum what I can when I do a water change. I have been doing weekly water changes (about 7%) and its amazing how cloudy the crud is that I vacuum up.
cincyreefer
Active Member
If it gathers nutrients over time, then it only makes sense to gravel wash (vacuum) the substrate.
Two things: 1.) If you are constantly stirring it to vacuum it, then the DSB won't be able to process nitrate.
2.) If much nitrate has been processed and you vacuum it, then you are running a risk of letting any hydrogen sulfide to be released into the water column.
Two things: 1.) If you are constantly stirring it to vacuum it, then the DSB won't be able to process nitrate.
2.) If much nitrate has been processed and you vacuum it, then you are running a risk of letting any hydrogen sulfide to be released into the water column.
razoreqx
Active Member
Originally posted by EG_HATCH
yup
Anyway, so the underground plenum system is probably my best option?
Oh, and Razor, howd you do that piping undeneath you cc?
I took a piece of 1" PVC and used a small kit type saudering iron to melt little tiny holes all through it.
All you need is one piece the length of the bottom of your tank.. (this is where your holes go) and elbow to a tube connector at one and a cap at the other. All available at your local home depot or Lowes.
Just connected the tubing from your return pump to the hose.
I kept the L connector that I got with my pump. I put a hole in that just above the water level so that suction will break if the power goes out.. ITS IMPORTANT to make sure you have this hole... Or read the I FLOODED THE ... thread i started ...
Also make sure you cover the PVC with a thin 1/2 to an 1 of CC so that water is drawn into the PVC evenly across the entire bottom.... Then your deep sand bed on top of that.
You will be suprised how much sludge you'll pull from the bottom in just a COUPLE weeks!
razoreqx
Active Member
Oh and if you ment how did i get the pipe in there? I built this in my fuge when I set it up.. I only use a small layer of substrate in my display tanks.
I DONT recommend running this setup, in the display, if you already have your display tank setup with a DSB. You will release those gases and will crash the tank .
You need to empty the display tank of creatures and corals before you can install this setup If you have a substrate already setup..... This will cause your tank to cycle again if you dont take heed to my warning
I DONT recommend running this setup, in the display, if you already have your display tank setup with a DSB. You will release those gases and will crash the tank .
You need to empty the display tank of creatures and corals before you can install this setup If you have a substrate already setup..... This will cause your tank to cycle again if you dont take heed to my warning
doodle1800
Active Member
My 55 will have no substrate come summer. .. however - I went to the Shedd Aquarium last week and talked to a tank keeper. They siphon off the sand with a filter tube just off the top layer of the sand. I did not see one SW setup without a substrate. I would think if you want a dsb filtration system, use a fuge. My .02