Play Sand?

[Driftwood]

I was under the understanding that the lower parts of a DSB were good for growing the anarobic bacteria that consume nitrates. I had a DSB in my 29 and I had no nitrates, now that I've moved to a 75 and have a shallow snad bed my nitrates keep climbing...

What is the best method in your opinion to remove Nitrates, besides water changes? I do a 10% a week change, but I'd rather see the nitrates consumed by the system.

I thought I should mention that I don't even have a spot of red slime 3 days after starting the limewater drip. Simply amazing, the stuff used to cover a good portion of the tank... Now I just have to get rid of the hair algae, but I don't think that looks as nasty as the bacteria did. It the lime water okay to drip all the time or do I need to constantly test and adjust the drip? Right now I have basically used limewater to replace my top off, I drip about as much per day as I evaporate. Everything in my tank is looking healthier and more extended also.

Thanks!

 

[bunsenburner]

I think the depth of the sandbed required for anaerobic bacterial growth is not well defined. Most denitrifiers requires trace amounts of oxygen. Bacteria tend to live in tight layers (microbial mats) where the nutrient amount, oxygen level, etc is ideal for the respective species.

Mt thoughts are is that the overall area of the sand bed is more impartant than the depth (as long as you have a couple of inches of sand bed) for the anaerobic portion of the nitrogen cycle. The rate of exchange of nutrients at the water/sand bed interface is likely the limiting factor.

 

[spotfin]

I was under the impression that the bacteria that break nitrate down live in anoxic areas, or areas with very little amounts of oxygen, as opposed to anaerobic areas which have no oxygen? I would agree that the surface area of a dsb is more important than depth as long as the sand is deep enough.

 

[Driftwood]

I'm going to throw in 40 pounds of sand and see what that looks like. It is good to know that it doesn't have to be that deep. More room for macro!

 

[Hedonist]

Rob Toonen did a talk on DSB vs SB at MACNA and at a BRS meet... he found it did not make much of a difference in his studies... the only difference was that in a DSB the alk was a little higher but not really signifcantly......

Dave I have a tank I am takiing down if ya need some LS

Denise

 

[jacksonsmom25]

I have a barebottom tank, and have no nitrates.

 

[jessiesgrrl]

Aerobic bacteria live on the top of the sand and break down the ammonia. Then the anaerobic bacteria cycle the nitrite into nitrates. Anaerobic bacteria by nature cannot live in an environment that has contact with oxygen, which is why there aren't any in a bare bottom tank- these are the nitrate producing bacteria in your tank.

Most of the debate about deep versus not so deep sand bed centers around whether or not a deeper sand bed provides a larger breeding bed for anaerobic bacteria, since no oxygen reaches most of that type of sand bed. I haven't seen any research yet that has proven that a deeper sand bed breeds more anaerobic bacteria than it's less deep neighbor. However, what it does do for sure is displace more water in your tank that you would have had for purposes of dilution.

My personal theory is that the anerobic bacteria can only live where TWO things happen- nitrites reach them, AND there is no oxygen. Thus, no bacteria would live on the very bottom of the tank anyhow since all the nitrites would be constantly converted to nitrates by the anearobic bacteria above the extreme bottom of the tank.

 

[jessiesgrrl]

Okay, that was my Stuart Smalley "Deep Thought" for the night, if anyone remebers the old Saturday Night Live... no more wine and cheese for me tonight... LOL