My remote sandbed

[stanlalee]

Originally Posted by JDL
http:///forum/post/3036804
you may want to do some more reading. On a site the mods will edit out of this post, they are talking about a new layer of bacteria in sand beds. I cant explain it exactly but they mention that dsp are bad and you can get the same effect using ssb.
well what they really said was there is such a thing as a too deep DSB and at a certain depth stuff happens that is counter productive to whats going on in the first 6" or so. they also found nitrate assimilation from aerobic bacteria to be sufficient to keep nitrates at zero (shallow sand bed) and work faster (not to be confused with better) than a DSB. there are way too many articles, studies and actual practices with deep sand beds for anybody to conclude they arent effective based on that ONE study. the study never concluded they dont work.
I always thought the lack of need for anearobic bacteria to consume nitrates was obvious anyway. As many nitrate free tanks with shallow or no sandbeds and small size rock with very little anearobic areas it seemed logical in practice large anearobic areas arent REQUIRED for low nitrates. Now with the popularity of carbon dosing utilizing bacteria blooms for assimilation of nitrates it seems even more obvious. these bacteria obviously arent anearobic and consume nitrates from the water column. None of that changes the fact that deep sand beds can be effetively utilized to eliminate nitrates.

 

[natclanwy]

I would like to see this article that clams aerobic bacteria can process nitrate, that goes against everything that I have read about aerobic and anerobic bacteria and if it is only a single article I would be highly suspect of the source. Since you can't post the link post the name of the article and the author I should be able to find it from there.
Tanks without a DSB are still utilizing anerobic bacteria to process nitrates and usually are utilizing macro algaes for nitrate removal to help offset the reduced availability of denitrifying bacteria. Water changes are usually an important part of nitrate control in these tanks too.
Carbon dosing is a completely different animal, the addition of carbon causes a different strain of bacteria that is not normally present in large quantities in the tank to grow. The Nitrate and Phosphate aren't processed they absorbed into the structure of the bacterial cell similar to the process macro algae uses. The nitrate and phosphate are still present in your tank until the bacteria are removed through the use of a protien skimmer.

 

[stanlalee]

Originally Posted by natclanwy
http:///forum/post/3038384
I would like to see this article that clams aerobic bacteria can process nitrate, that goes against everything that I have read about aerobic and anerobic bacteria and if it is only a single article I would be highly suspect of the source. Since you can't post the link post the name of the article and the author I should be able to find it from there.

I went back looking for it. they didn't say aerobic bacteria were responsible for nitrate processing. they did find nitrates lower in shallow sand bed testing and did not have an explanation at this point just some theories:
Perhaps the most perplexing result from this experiment is the significant interaction of sediment particle size and depth in the aquaria. The simple prediction based on sandbed depth would be that deeper and finer sediments should always have reduced oxygen penetration and therefore increased nitrate processing capacity (Toonen, 2000a; b; Shimek, 2001; Delbeek, Sprung, In press). Therefore, it is hard to explain why deep, coarse (27.41 mg / L ± 6.89 SE) and shallow, fine (20.42 mg / L ± 6.89 SE) sediments have the highest average final nitrate concentration, while shallow, coarse (12.08 mg / L ± 6.89 SE) and deep, fine (0.67 mg / L ± 6.89 SE) sediments consistently had the lowest final nitrate concentrations. Nitrate reduction in deep, fine sediments is easily explained by reduced oxygen penetration to the sediments. However, the increased final nitrate concentrations in aquaria with deep, coarse and shallow, fine sediments relative to the shallow, coarse treatment is harder to understand

Carbon dosing is a completely different animal, the addition of carbon causes a different strain of bacteria that is not normally present in large quantities in the tank to grow. The Nitrate and Phosphate aren't processed they absorbed into the structure of the bacterial cell similar to the process macro algae uses. The nitrate and phosphate are still present in your tank until the bacteria are removed through the use of a protien skimmer.
I agree. they are in the tank but in the bacteria and not available for use or test results. I never said they could convert nitrates chemical make up like a DSB, they are however aerobic and all I said was they could maintain zero nitrates (I left out with utilization of a protein skimmer but thats almost a default item these days and assumed it as a given). Carbon dosing greatly proliferates the number of those strains of bacteria but the purpose of carbon dosing is to drop nitrates and phosphates "quickly". once nitrates/phospates drop carbon dosing is dropped way down where a balance between nitrate/phosphate production and the amount of those strains of bacteria required to keep them at zero via low carbon dosing is maintained. the carbon is only needed to proliferate the strains of bacteria where there is a problem or desire to cram nutrients (tanks with high nitrates already or to allow huge feedings without rising nitrates). what about the tanks that never had high nitrates or excessive nutrients with no DSB or large anaerobic areas that slowly fall from low to zero nitrates over the course of six months as they mature. there's been no evidence of a shortage of carbon sources available for certain strains of bacteria in tanks that dont require he-man reductions of nitrates in a short period of time. who's to say its anaerobic areas and its not enough carbon already present/introduced normally to maintain a balance that keeps nitrates at zero without daily maintenence shots of carbon? I believe all my tanks have fallen into that category since up to five months ago I've never had a DSB or large pieces of liverock with large anearobic areas (or even a fuge in one case) yet nitrates have always fallen with time to eventually zero. even with shallow crush coral, no fuge and increasing stock my first reef slowly dropped from 10ppm to zero over a 3-6 month period with no maintence changes or large anaerobic areas. this not a new tank either where it could just be atributed to fresh liverock die off completion. its a tank that had been up a year as fish only without a skimmer converted to a reef when the reductions took place. None of my other tanks have ever had nitrates above 10ppm period. might be something different all together who the hell knows for 100% certain. I'm doing the carbon/bacteria thing now (biofuel and micobacter7). we will see what that turns up. then I'll have covered berlin SSB, remote DSB, Macro algae fuge and carbon. so far NONE have not worked well.

 

[salt210]

ok. I had to add a PH to create more flow within going over the sandbed and as of right now I am trying to figure out some obstacles with the plumbing. Prior to this I had a T connector off of one of my overflows and decided to use this to feed the bed. this is causing a bubbling effect and I am going to find a way to eliminate this which I believe can be done by just getting rid of the T and hooking the hose directly to the drain from the overflow.

 

[salt210]

ok. it is now up and running. with the plumbing I ended up leaving at it is. I will give it till tomorrow and then test the params and see if there is any change and then after that I will test every other day.

 

[salt210]

 

[salt210]

I tested my trates on friday and saw a slight decrease. They were around 30ppm and now the test reads 20ppm. I will test again on monday.
The sandbed ended up being 7" after the 2 bags of sand.

 

[natclanwy]

I doubt the drop had much to do with the new sand bed, it takes several weeks for a DSB to start populating anaerobic bacteria in large enough quantities to effect you nitrate levels. The reason being when you install your sand bed the sand is saturated with oxygen and aerobic bacteria will inhabit the sand first and begin to use up the available oxygen. Once the oxygen has been depleted the aerobic bacteria will begin to die off and then the anaerobic bacteria will begin to populate the sand bed. It takes about six months for the sand bed to reach its full nitrate processing capacity so I wouldn't expect to see any large changes in you nitrates due to the sand bed for at least a couple months.

 

[salt210]

thats what I have been thinking. I tested today and there hasnt been any change. I have been doing weekly water changes, so that could have been it.

 

[zelfin]

I have read some of these topics. I understand that the smaller the sand the better the filtration (more surface area).
But if you use a thicker sand, does it then use more than the first 6-8"? Say like crushed coral that is more open. can it then use the first say 12-16"?
Just a thought. I like this idea and am an avid DIYer. But the substarate i have laying around unused is larger than the suger sized sand yous recommend.

 

[salt210]

what size are you talking? going big will make it easier for particules to accumilate within the bed and could cause problems down the road