DSB in a bucket for nitrate control

[eshook]

Boat,

I agree that we are agreeing ;o) We could use another idea proposed by someone else (sorry for not giving credit, someone else deserves it because this is not my idea) and split the container in half with a sheet of plastic/acrylic. Then put a hole the size of your input size (I would suggest 1") in the bottom of the split. Put an enter and exit bulkhead on the top. The water will enter through the top bulkhead will go down into the sand and through the small hole at the bottom and come back up. By doing this you should be decreasing the amount of oxygen through the entire journey. In theory the second half would be an entire low/no oxygen zone. If that is the case that would be a very effective method because you would be exporting *all* that water... Plus by splitting it you don't have to worry about sand exiting the bottom pipe.

Variation: Instead of putting the hole in the bottom you could put it in the middle and reserve the entire bottom (both sides) to low/no oxygen areas. Personally this would seem like a better solution you get the best of both worlds since the above method is unproven.

For this to work I presume you would have to meet 2 conditions:
1. Big enough container for water to go from high oxygen to low/no oxygen
2. slow enough flow for the oxygen to be removed by fauna while going through the sand.

Most people disagree that this would work boat but I think if you had a big enough container (with enough sand) and had *really* *REALLY* slow flow it just might work.

Since you have the materials why don't you try it and tell us what you find.

Eric

 

[Spuds725]

I'm not saying that running slow flow through the sand won't work, but I think you guys are missing the point of this method-- its a purely bacterial sand bed-- not intended to be a live sand bed at all--- part of the set up is a fairly fast flow over the top of the bed to keep detritus from settling in it at all.

I don't think its necessary to pump water through the sand. If anything I'm betting you will get a nitrifying bed then a denitrifying-- it won't take much flow to oxygenate the sand---

If the concern is bio capacity in a taller bed-- then a plenum setup with flow across the top and the bottom may or may not increase the denitrifying capacity-- I'm still not convinced that the nitrates won't dilute there way all the way to the bottom in a traditional bucket DSB-- nitrate molecules and water molecules should have no problem moving around the sand grains--- and dilution of the nitrate is what is causing it to migrate into the sand-- read my post several pages back about the driving force (2nd law of thermodynamics) in the dilution of the nitrates into the sand bed....

 

[Boat]

Spuds,

What we're really trying to do is optimize the anaerobic zone of the bed where nitrate is converted to nitrogen gas. Your "dilution of the nitrates into the sand bed" is one approach to feeding the anaerobic zone and slowly moving flow through it is another. I bet both methods will work. The only way to determine which is more effective would be experimentally. Unfortunately my tank doesn't back up to a utility room so I don't have room to try it out.

 

[barryhc]

Both types of system will work. Both systems can be run simeltaneously in one container as well. What is the point ? I don't know, we're just trying to learn here.

The "flow over" system works correctly, automaticly. It will work with high flow, or low flow. High flow just keeps solids out to some degree. You could use filter floss and change it once daily, or use the effluent from your skimmer, for the same purpose.

Flow through, will work well also, BUT it does not work correctly, AUTOMATICLY. The right combination of flow to volume AND depth is crucial to have the method work at all. Oxygen level testing of the effluent, is necessary to determine flow requirements, and should be less than 1 mg/l or lower, for denitrification to occur.

If "flow thru" ONLY is used, then based on flow restriction to maintain proper hypoxic oxygen levels, the total amount of denitrification may be severely restricted.

A combination of both would likely work the best, but the added value of the Flow thru may not be justified in terms of the complexity.

However, IF , The combination method was used, and the low flow thru, was wasted, rather than returning the small volume to the tank, THEN , Phosphate reduction would be improved as well, along with removing potential sources of Hydrogen Sulfide and heavy metals. :idea:

This would increase the life of the RDSB exremely, potentially even indefinitely.

This would be my favorite choice.

> Barry :beachbum: :thumbsup:

 

[eshook]

Great idea! If we used both systems in the same bucket and removed what came out of the bottom maybe we could improve our overall system?

Perhaps use the exact same method except attach a ~1/8" (or severely restricted hose) drip line at the bottom of the bucket and have it drip into a drain.

Excellent idea barry! Anyone got a bucket and willing to run some tests?

 

[barryhc]

Just use any size tube you want, and restrict the flow with a hospital type flow restrictor ( pinch type ) or anything else you like.

Set the flow to a daily amount that you like. The amount of water change you want to have is your high limit. You might as well start there. Say you want 25% per month. Randy Farley has proven that daily changes are "no less than" 72% as effective as monthly "one time" water changes. :idea:

So, a 35% total amount of wasted water split into daily amounts, is equivalent to a one time 25% water change. It is actually a better method for water changing for various reasons.

Anyway, 80% of 100 gal. = 80 gal. . You do have sand and rocks in your tank don't you? at least rocks. Now, 35% of 80 gal. is 28 gal. , divided by 30 = Oh Heck, a gallon a day.

Test the effluent for oxygen firstly, to be less than 1 mg/L, and reduce flow as required to get below this number at a minimum.

Then test for whatever else you're interested in. The results could tell you a lot eventually. Bother Randy and/or Anthony about what the numbers either do, or should mean.

From there, you have one heck of a chemistry set to play with. Most anything that checks higher than in your water column, is being removed from the tank. Other compounds could be accumulating in the bed, and being "reduced" from levels in the water column, even though they do not show up higher in the effluent.

In this case, reduction in water column "test levels", would be the indicator of compounds being stored in the bed.

The surface area at the top of the bed is still going to have the most immediate impact on Nitrates directly, so don't skimp there.

> Barry

 

[NicoleRM]

So are there any recent updates from people who have tried this?

 

[SaltwaterDaddy]

To add to this idea of waste water thru the bottom of the RDSB and water changes. Just set up another "auto fill" tank with the correct amount of dissolved salt. Keep a small power head circulating the salt water. Setup a drip method with the same number of drips per minute as the waste water (assuming same size hose) and you have an automatic water change system. By doing this, you don't have to be a math wizard ... what ever the drips are going out in the waste, set the new "fresh" salt water drips to be at the same rate. "Automatic water changes ..." Reef keeping just gets easier and easier

 

[Spuds725]

<a href=showthread.php?s=&postid=6604971#post6604971 target=_blank>Originally posted</a> by NicoleRM
So are there any recent updates from people who have tried this?

I'll try to test my water real soon (been real busy)-- mine has been in for 3 1/2 weeks so the bacteria population should be coming up now--- my trates were about 30 ppm when I put it in on Jan 3rd.... I'll definitely post back here with my results.

Regarding the flow through discussion-- I'm not saying it won't work, but setting it correctly (flow wise) might be a pain and hard to replicate (for others)-- too much flow and you will have an aerobic bed...

If I ever go for a PhD in marine biology I will run extensive experiments on this

 

[lendef]

I have an enclosed container with a fairly good flow rate. This is setup on the outlet of my UV sterilizer. I have been leaving the sterilizer off. I need to know if I turn on the sterilizer will this stop the bacteria in the dsb from forming. Also, how deep does it need to be. I decided to use a Rena xp3 which is equivalent to I believe 4 gallons. I was too concerned that the tank I had set up underneath my display would at some point overflow and make a mess. I removed the media components and filled with sand. Put the final compartment and filled with sand1/2 and put the fine pad at the top. Now I am going to sit on it for 4 weeks and keep my fingers crossed. Can anyone think of anything I forgot.

 

[barryhc]

Having a UV running from the beginning, in front of the DSB would surely slow down the initial growth of the bacteria populations. However, once the bacteria get going, they can feed on the nutrients in the water, whether it includes live or dead bacteria.

So, at this point, turn it on of you like,

> Barry

 

[lendef]

Thanks Barry. I think I'll leave it off for the first 3 weeks. Knew I could get an answer here. Thanks again

 

[Spuds725]

<a href=showthread.php?s=&postid=6604971#post6604971 target=_blank>Originally posted</a> by NicoleRM
So are there any recent updates from people who have tried this?

Ok-- I tested my water-- (its been 26 days since I added my bucket DSB)--

My nitrates are virtually unchanged-- about 30 ppm-- but at least they haven't risen

Hard to say if its working as the accuracy of nitrate test kits isn't very good that high... (I checked it with 2 different kits)-- it might need more time to come up or I might need to add a second one-- I have one bucket with 50 pounds of sand running on my 135 gallon tank.

I am not running a fuge or macro right now (will be adding one soon just need some free time)..I do use RO/DI water so my nitrates are coming from my feeding habits-- I do feed my fish well-- IMO a fat fish is a healthy fish...

This tank has been set up for just over 3 1/2 months (upgraded from a 72) and has about 180-200 pounds of live rock.

I surprisingly don't have an algae or cyano problem-- just a bit of diatoms on my sand and glass.

I'll post back an update in a few more weeks.

 

[barryhc]

Spuds, I don't think your set-up has had enough time yet. My tank took about 6 mos. to start dropping Nitrates. I had a considerable bioload in the tank. Be patient, and keep feeding to a minimum. You could feed a small amount only every other day, and the denitrification would "come on sooner", and it won't harm your fish at all.

> Barry

 

[KEstep]

I agree with Barry. Give it a little more time. Mine has been on for 2 months now and it dropped mine from 40 to 30. I figure a few more months and it will be doing better.

 

[Airman]

<a href=showthread.php?s=&postid=6605630#post6605630 target=_blank>Originally posted</a> by SaltwaterDaddy
To add to this idea of waste water thru the bottom of the RDSB and water changes. Just set up another "auto fill" tank with the correct amount of dissolved salt. Keep a small power head circulating the salt water. Setup a drip method with the same number of drips per minute as the waste water (assuming same size hose) and you have an automatic water change system. By doing this, you don't have to be a math wizard ... what ever the drips are going out in the waste, set the new "fresh" salt water drips to be at the same rate. "Automatic water changes ..." Reef keeping just gets easier and easier

Saltdaddy,

Why would you throw away the water that just went though the RDSB filter and is nitrate free? This so call "waste water" is most likely the cleanest water in your system.

My RDSB lasted about two weeks. I build a good design using Zenman's method two layers of substrate. The bulkhead fitting would leak when I moved the power head to change the prefilter. I took all of the sand and added it to my refugium. I should get the same benefit.

 

[eshook]

I believe Barry can chime in on this but the water coming from deep in your RDSB will not be the cleanest water in your system. If you would like more reference to this you can read this thread:

http://reefcentral.com/forums/showthread.php?s=&threadid=673910&perpage=25&pagenumber=1

If you don't want to read the thread, basically a bunch of "nasty stuff" builds up in the depth of the RDSB and getting rid of it (without disrupting the bacteria that naturally form deep in the bed) would be most beneficial for everything.

My $0.01 (after taxes)

 

[barryhc]

<a href=showthread.php?s=&postid=6624283#post6624283 target=_blank>Originally posted</a> by Airman
Why would you throw away the water that just went though the RDSB filter and is nitrate free? This so call "waste water" is most likely the cleanest water in your system.

You are not catching "the jist" of the "wasting" approach. Neither the "Flow over" water from the "Standard applicaton" of RDSB, nor the "Flow thru" water, from the "wasting" version is going to be "devoid" of Nitrates.

The Flow "Over" version will cause Nitrates to become lowered over time. However, the difference between incoming water and outgoing water is assuredly undetectable! ! ! Over time, the Nitrate level will reduce. This is likely to take 2 to 6 months to develop.

The Flow "Thru" version, MIGHT actually reduce the level of Nitrate to zero ( in the effluent itself ), but, it is likely to have elevated levels of phosphate, and many of the constituents that lead to Hydrogen Sulfide production, as well as a "goodly" amount of heavy metals. The amount of flow in a flow thru version is really not enough to significantly affect nitrate levels in the water column anyway, unless an unreasonably huge " bed" is used, or if "feeding" is utilized, which would raise the levels of other "nasty" effluents.

My RDSB lasted about two weeks.

Not a "fair trial" to be sure.

I build a good design using Zenman's method two layers of substrate.

And what is the point of saying so when you didn't allow sufficient time for it's bacteria populations to develop?

The bulkhead fitting would leak when I moved the power head to change the prefilter. I took all of the sand and added it to my refugium. I should get the same benefit.

You could get a similar benefit, but not including the lack of light, which helps to avoid algae growth on the surface of the sand.

> Barry

 

[Airman]

I know that it was not a fair trial because of the time. I tried to fix the leak in the bulkhead with silicone II but it would seep when I flex the hose to change the prefilter. Instead of having a possible flood on the carpet I would prefer to have the DSB in my refugium. I have not had a problem with algae growth in my refugium. I like to have the DSB in the refugium because there is a greater surface area for the water to flow across. I realize that it is no longer a RDSB and does not fit the necessary parameters of this thread but I'm still going to continue to read this thread.

coolness

 

[barryhc]

Airman, I think the greater surface area is a big plus, "most" believe that 4" is minimum for reliable denitrification. I think the RDSB is partly for people who don't otherwise have the surface area available for whatever reason , or who want to have it sealed out of sight, and or large systems where maint. is also reduced.

Many people have tried these in the past and have stated poor results, but I think that improper setup, and/or more often impatience has been the most common culprit.

> Barry