DSB in a bucket for nitrate control

[eshook]

Some people advise against washing the sand. If you wash the sand you will loose the smallest grains (i.e. the grains that will hold the most surface area per sq. in.) If you want to err on the side of caution you can wash the sand multiple times, if you want to be less cautious just give it a good rinse and if you're like me you will cut open the bag, let it dry out and pour it into the bucket )

I just bought some SD from a local clubber and will be making mine shortly...

 

[Boat]

Sorry if this has been covered but it's long thread. Has the possibility of slowly trickling water through the RDSB vertically been discussed? This would be an attempt to mimic a "tile field" or coil denitrator approach.

 

[mmmmsushi]

That's a negative, because forcing oxyigenated water through the sand wouldn't allow for the anaerobic area that is cricual to denitrification.

 

[Boat]

That's why I would trickle it through. And I was thinking of a relatively deep bed - maybe 3 ft - so that the water would be deprived of oxygen as it passed through. Maybe using a 15 gal barrel. If you take a quick look at my gallery I use one for auto-topoff.

 

[Kinetic]

Boat: a bunch of this was discussed earlier. probably best to look back on the lengthy discussion of it =)

In a nutshell, trickling through is definately not the best way to get a RDSB to work. Few think it would.

 

[eshook]

Boat

I think you would get better results taking one of the 15 gallon barrels, filling it full of sand (minus ~7" on the top), tipping on it side (supported so it doesn't roll ;o), and running pipes from that. It should give you *plenty* of surface area for the water to interchange with the RDSB and will give you *plenty* of sand to process everything...

Just an idea ...

 

[barryhc]

<a href=showthread.php?s=&postid=6584258#post6584258 target=_blank>Originally posted</a> by Boat
That's why I would trickle it through. And I was thinking of a relatively deep bed - maybe 3 ft - so that the water would be deprived of oxygen as it passed through. Maybe using a 15 gal barrel. If you take a quick look at my gallery I use one for auto-topoff.

This can be done, it is also a bit of a balancing act. Denitrification will occur, so long as an oxygen level of 1 to 2 mg/l is achieved somewhere within the depth of the bed. This will happen in as little as 2" with appropriate sand ( or substrate ).

It can also be detrimental if not properly thought out and controlled. Various nasty processes can and/or do occur "deeper in the bed", in the Anaerobic zone, and trying to become educated in this regard, is like trying to pull an oxcart through the center of the sun without drying out the wheel grease.

I'm in favor of the "flow bed", but you will have to educate yourself on this. Nobody here or anywhere, has a handle on what is happening in the Anaerobic zone of a reef aquarium.

> Barry

 

[eshook]

Proposal:

This is an outrageous proposal but I am curious what other people think of it. What if you used a plenum type technique to layer the sand/water? For instance assume a box 4' high with the following layer (sorry this is a rudimentary sketch, if you need more explanation just say so)

---------- top of box
~~~~~~ water
OOOOO high oxygen sand
............... low/no oxygen sand
OOOOO high oxygen sand
####### plenum type material to hold up sand
~~~~~~~ water
OOOOO high oxygen sand
............... low/no oxygen sand
OOOOO high oxygen sand
####### plenum type material to hold up sand
~~~~~~~ water
OOOOO high oxygen sand
............... low/no oxygen sand
------------ bottom of box

Basically you take a box and put plenum type material to hold up the sand and run water both above and below the sand. Instead of the bottom being the low/no oxygen zone it is the middle of the sand bed. You double (triple, etc) the amount of surface area that the water interacts with. This could be done by pumping water to the top and then piping water down each level until the bottom (using gravity) You could use pipes with many holes to "direct" the water flow in the middle sections. You could also vary the depths to make more or less low/no oxygen layers. Maybe this will produce a varied array of creatures and processes that will be maximally beneficial?

I don't believe anything like this has been mentioned so maybe it would work? Any big problems, suggestions?

 

[Ramble On Rose]

Has anyone set up a RDSB on a 300+ gallon system yet? I read earlier in the thread about the store and Anthony's recomendation to use a 55 gallon tank or tub. My question is I have about a 320 gallon total system volume setup and I have a 33 gallon trash can I could use for to setup a RDSB. Later in the thread there are many people (not Anthony) mentioning that there is no benifit to deeper beds. Specifically I believe someone said that anything over 8" is a waste. Is there any truth to that? Isn't even a 5 gallon bucket over 8" deep? It would be a lot easier to use a garbage can in my case then say a 55 gallon aquarium because of the space I have available. Thanks.

 

[eshook]

Ramble On Rose, I don't think anyone knows the processes well enough to mention that deeper than 8" will be beneficial. I think we all agree that there *is* a depth that if increased will no longer be beneficial but I don't think anyone knows how deep it is. Most people agree that anything is better than nothing.

Personally if I was you, I would fill the can up with as much sand as you have (whether you have it half full or all the way) and then put the exit pipe about 4" above the sand line. This will give room for the water flow. Again my suggestions take them as you will.

 

[barryhc]

Well-well-well, Now some real thinking is starting to occur. This is of course, how municipal denitrification has been handled for years, and it amazes me how few catch the connection.

Search for a thread called "Biological Phosphate Removal", and you will find many interesting links in this regard.

> Barry

 

[Ramble On Rose]

<a href=showthread.php?s=&postid=6585024#post6585024 target=_blank>Originally posted</a> by eshook
Ramble On Rose, I don't think anyone knows the processes well enough to mention that deeper than 8" will be beneficial. I think we all agree that there *is* a depth that if increased will no longer be beneficial but I don't think anyone knows how deep it is. Most people agree that anything is better than nothing.

Personally if I was you, I would fill the can up with as much sand as you have (whether you have it half full or all the way) and then put the exit pipe about 4" above the sand line. This will give room for the water flow. Again my suggestions take them as you will.

Well the can itself is about 3 ft tall. I currently have 2 five gallon buckets worth of sand left over from my upgrade so I would be buying a significant amount of new sand either way. My original plan was to do as you suggested and fill the thing almost all the way up with sand, lets just say 2 feet worth, and then have the water flow on top of that. I'm not worried about the cost of sand or anything, just that it would not be as effective as if I were to go with some other option like a longer and shorter container. Thank you for your input.

 

[barryhc]

<a href=showthread.php?s=&postid=6584978#post6584978 target=_blank>Originally posted</a> by Ramble On Rose
Has anyone set up a RDSB on a 300+ gallon system yet? I read earlier in the thread about the store and Anthony's recomendation to use a 55 gallon tank or tub. My question is I have about a 320 gallon total system volume setup and I have a 33 gallon trash can I could use for to setup a RDSB. Later in the thread there are many people (not Anthony) mentioning that there is no benifit to deeper beds. Specifically I believe someone said that anything over 8" is a waste. Is there any truth to that? Isn't even a 5 gallon bucket over 8" deep? It would be a lot easier to use a garbage can in my case then say a 55 gallon aquarium because of the space I have available. Thanks.

Sand beds have a tendency to "fill up". Deeper beds take longer to fill up.

I suggest following eshook's idea of increasing the surface area, as this will increase the processing capacity, and in many instances may increase the RDSB "life" as well.

> Barry

 

[eshook]

barry,

I will be checking out the information! Thanks for tip. I don't mind reading through boring documentation as long as I learn something. I'm just hoping to help people with big tanks (such as ramble on rose) where taking twenty 5 gallons buckets and daisy-chaining them would not be effective. Instead use one or two 15 gallon barrels and have 3-4 layers would be better use of space I would think. I also wonder with having water on both top and bottom if we could avoid crashes or other benefits would come about.

 

[barryhc]

Actually I think this could work very well, but the "balancing act" is still there. You have to consider grain size, bed thickness/2 ( in this case ), and flow of course. Flow may not be that "touchy", if it remains "across the surface" and not "thru".

I think "across the surface" is the better technique by itself, since it maximizes capacity. "Thru techniques" would maximize longevity at the expense of effeciency.

> Barry

 

[eshook]

I agree with the across the surface it should maximize surface area on the sand with the least amount of resistance (i.e. no pipe walls) Grain size should also be a consideration. I wonder if having different layers in increasing or decreasing thicknesses would improve anything?

thin
medium
thick

or

thick
medium
thin

I don't know which would provide the best solution. For some reason my intuition is telling me the second would provide a more stable system but I have nothing to base this on. I just purchased some SD so in the coming weeks I will try to construct something that will allow us to experiment with the above idea. Pending no-one proves it wrong in the mean time.

 

[barryhc]

<a href=showthread.php?s=&postid=6585519#post6585519 target=_blank>Originally posted</a> by eshook
I agree with the across the surface it should maximize surface area on the sand with the least amount of resistance (i.e. no pipe walls) Grain size should also be a consideration. I wonder if having different layers in increasing or decreasing thicknesses would improve anything?

Boy, you just can't stop hitting the nail "right on the head" can you ? ? :lol:

Different layering schemes can reap some benefit depending . . . .

If you're only going for "bacterial denitrification", then rather fine "oolitic" is probably the ticket. Ck. with Anthony he's sharp on this. if you're trying to maintain "fauna" that is a bit more difficult, but maybe not necessary ( for the RDSB ). RDSB does not need to run the same as DSB in your tank, or refugium.

I happen to believe in layering for DSB, but not necessarily for RDSB. We can can get into it more, but here is no "magic bullet" and any solution requires monitoring until "proven".

> Barry

 

[Boat]

I took off a couple of hours to read through some past posts and now I'm two pages away from where I joined in here.

Koden - I can't find anything in the first twenty pages that is a valid argument against the "flow through" scheme. In my opinion (and only my opinion) I feel that once tuned, this system would be more efficient than the "flow over" design. I feel the "flow through" system has been modeled in a different application. ie. Your typical backyard septic system, 75 feet away from a typical water well. The trick would be finding a bed depth vs. flow rate so that nitrate would be consumed before reaching the discharge point back to your sump.

 

[eshook]

I think the only opinion was that if you have water (high in oxygen) flowing through the sand that you could never build up a low/no oxygen zone. I suppose if you created a deep enough system and the flow was slow enough such that by the time the seeping water got to the bottom it would be low/no oxygen. If that were the case then I would suggest getting some 4"-6" pieces of pvc about 5' long and filling them full of sand. Reduce the ends to ~1/2" and push water up to the top and let it trickle through the sand out the bottom. With 5' of sand by the time the water gets to the bottom it should be low/no oxygen assuming you don't connect a mag 36 to it ;o)

What do the experts say?

 

[Boat]

eshook,

Actually you and I are agreeing - we're just taking different approaches to the same solution. You're using a 6" diam. tube and I'm using a 24" diam tube. MSU vs. Michigan bball is on so I'll be back later.

Steve