What is NNR and DSB?

[Tanzy]

may i know what is DSB? and NNR?

All the jargons. Me newbie here. Thanks for enlightening me.

DSB = Deep sand bed

NNR = Natural nitrate reduction

DSB is a form of NNR, so is the plenum method (also known as Jaubert method). NNR is a form of nitrate export in the aquarium by using natural denitrification processes found in sand beds or live rocks.

DSB usually involves a layer of sugar fine sand of at least 6" thick. The thick layer of sand allows anoxic and anaerobic layers to develope where denitrification (conversion of nitrate to nitrogen gas or nitrous oxide

which bubbles off into the atmosphere) takes place. The upper oxygenated layers take care of nitrification (convertion of ammonia to nitrite to nitrate") and help consume oxygen and maintain low oxygen concentration for the lower layers.

Plenum or Jaubert or Monaco method, named after Dr. Jean Jaubert of l'Institut Océanographique de Monaco, is quite similar to DSB, except a plenum or a layer of water is maintained at the bottom of the sand bed to prevent anaerobic layers from forming. The sand used is of a coarser grade similar to Size #1 crushed coral.

What DSB and Plenum method is trying to acheive is low or almost zero nitrate concentration in the water to simulate natural reef conditions. This low level of nitrates prevent algae blooms, improve coral growth and reduces stress on tank inhabitants.

[Valleyman]

Tanzy,

What is the ideal coral sand size, #? to use for DSB ?

I have plenty of coarse sand left over from my freshwater tank. Is it ok to lay these as the bottom layer under the fine coral sand so that I can build up to at least 4" ?

[Tanzy]

Valleyman,

AT thinks that #1 is good enough. After seeing some tanks with DSB, I feel that #1 is still too big. The ideal size according to Ron Shimek is fine sugar size. The sand bed looks more like a mud bed actually. Unfortunately, we do not have access to calcium carbonate sand of that size unless you use silica beach sand.

How coarse? The finer the sand the bigger the surface area per volume, so more bacteria can colonise the sand bed. Fine sand will pack down due to gravity and lift the coarse sand up too, so after a while your layer will invert with the fine sand at the bottom.

[TTBoy]

what abt argonite sand? are they fine enough?

[Tanzy]

Aragonite is the name for a type of calcium carbonate crystal. Aragonite sand means calcium carbonate sand. It comes in a variety of grade and size.

[TTBoy]

i saw argonite being sold in a LFS here. It looks finer than #1 but very expensive.

[Achilles Tang]

#1 sand is the finest coral sand available and should be more or less the best we can use as oolithic sand is unavailable.

If you go for even finer grains, sugar-sized (oolithic), you will get a mud-like sandbed which tends to blow up a lot more with currents which may irritate or even kill some corals should it cover their openings.

It would also make vacuuming of detritus an impossible task (for those who are in the habit) as your sandbed will lift off too!

Aragonite sand sold in LFS are ridiculously expensive. A full DSB with aragonite sand will be in the thousands of dollars. Believe me, I was considering that...

[wedgee]

If you go for even finer grains, sugar-sized (oolithic), you will get a mud-like sandbed which tends to blow up a lot more with currents which may irritate or even kill some corals should it cover their openings.

It would also make vacuuming of detritus an impossible task (for those who are in the habit) as your sandbed will lift off too!

Yeah, me friend got this smaller than #1 "sand" and used it in his Cichlid tank-ended up his water was cloudy almost all the time (due to the sand being blown around in the water column continuously!)

Now, he has thrown away the sand and used #1 instead

[wedgee]

Oh yah, forgot i had a question to ask u guys regarding DSB height; is 4" sloping towards 3" in the front enough for the bacteria to exist? I see small air bubbles in the front of the tank, esp after the first inch - does this show that the water is not flowing into this area? (making it anerobic?)

I am using #1 sand currently, and though i have some more spare sand, it hurts to pile up more cause its only a 3 ft tank and there's limited real estate...

[KingFish]

I have a 3 ft tank too and I know how you feel....

If you have a sump, you can pile it on there, I'm thinking six inches in my sump/refugium and maybe just keep it at 3 in the main tank.

Wonder if that works?

[wedgee]

If only i'd gone with a 4 ft and endured the nagging by the 2 women... At least u got a sump Rumor; me dont have the skills to DIY myself one (even though i have a spare 2 ft tank), nor the spare money to get a ready-made one (btw how much is yrs? Can ask the LFS to make one dat comes with the pipes, pump etc?)

I'm thinking u need a large area in yr sump to handle yr main tank NO3 (unless the 3" in yr main is enuff-same question again haha)???

[KingFish]

That Wedgee, I emphatise with you too.....

However, I WENT ON AHEAD NONETHELESS......

A man needs a hobby, and perhaps to keep his sanity/his own little sanctuary. AT has his little room and me, my Chamber of Secrets....

I'm pretty certain you can handle the DIY. Just pick up ideas from some of the 'sump' threads and you'll be itching to try.

My sump was customed together with my main and it costs me less than $100. The full works, pipes and pump will cost you, I'm doing that myself.

I hardly think the my sand bed is enough, as I'm sure many will concur. The sand in my refugium will cover roughly 28'x10'x6', am not too sure myself.

[Tanzy]

Come be that bad right? I had a 6" Plenum in my 2 feet thank! That's half way up the top already!

I won't buy the Caribsea aragonite locally because it's overpriced. If you want oolithic sand, go for beach sand instead. Real cheap or free. Strong current does blow #1 sand around, but only if the water is directed at it. I have pretty strong water movement in my tank and the sand bed remains intact. The surface of the sand moves and tumbles around but that's about it. Good too, since it prevents clumping.

AT,

You are not suppose to vacuum a DSB! The muck feeds the sand fauna.

[Achilles Tang]

I didn't say to do it. I said 'for those in the habit'. Sometimes, heavy detritus will pile deep into nooks and crannies and may be better to/easier to vacuum out rather then waiting for it to decompose/be eaten by sand fauna as it may quickly contribute to water pollution.

It may be done by those who see a distinct lack of sand fauna and having poor water circulation that doesn't see detritus being suspended and caught by mechanical filtration or skimmed out.

IMO, if sandbed fauna cannot process detritus in big quantities fast enough... get rid of it yourself if your filtration system can't.