Powerheads disturbing sandbed

[cobra2326]

As for aeration of the water, should I use the venturi that comes with the maxi-jet to inject air in to the water. I'm not using them now, b/c I've heard of people complaining of "micro-bubbles".

 

[chromafi]

If you buy a wavemaker to alternate the powerheads, you will not have the sandstorm. A sandstorm happens when powerheads intersect and sent the current up and down. When the jets alternate, the sand can only blow across the tank, not up and onto your corals.

Also, if you dont have a plenum underneath the DSB, you will not get great results and the DSB could poison your tank.
You need a body of water with very little oxygen for denitrification. The plenum as well as a nitrate reactor accomplishes this.

 

[bertoni]

There isn't any evidence that plenums work, and some evidence that they are harmful. A live DSB doesn't require a plenum to do nitrification. This thread has some notes I wrote on the topic:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=803686

 

[cobra2326]

From an article posted by the above author:

"Hydrogen sulfide will indeed be formed in the lowermost layers of a deep sand bed. It will NOT migrate up through the sediments to poison a tank. Hydrogen sulfide is an amazingly toxic gas, but that toxicity is exceeded by its pungent rotten-egg odor. The gas will have an exceptionally strong odor, and will seem overwhelming at levels well BELOW toxic amounts. If you can smell this stuff without it literally taking your breath away, it won't be at a harmful concentration. There is no real evidence to indicate that it may reach toxic levels in a deep sand bed."

Link: http://ronshimek.com/Deep Sand Beds.htm

 

[Aquarist007]

<a href=showthread.php?s=&postid=10426442#post10426442 target=_blank>Originally posted</a> by INCEPTION7
Capn,

There are two schools of thought here. 1) less then 1" of substrate (ooltic or other fine) will hinder the substrate from becoming a nitrate trap. 2) A substrate of more then 3" will have a denitrifying effect. The only thing about having a DSB is it must be maintained. I do not use a DSB in any of my tanks because of this. If the bed is not maintained (stirred lightly, replenished top layer every 6-8 months) it can cause a reverse effect and possibly crash the system. To me, the best things you can do to keep nitrates at 0 are keeping up with regular water changes, feed lightly, change filter media weekley and have a refugium that totals AT LEAST 10-20% of total water volume filled with macroalgae such as Chaeto that won't go sexual.

thanks --I agree with you--one question---implied from your answer is that a refugium takes the place of a deep sand bed---which I have----however what should be the flow rate out of the refugium to take advantage of its filtering capabilites--mine just trickles out to keep the bulk of the copepods in there reproducing.

 

[Aquarist007]

<a href=showthread.php?s=&postid=10439869#post10439869 target=_blank>Originally posted</a> by bertoni
There isn't any evidence that plenums work, and some evidence that they are harmful. A live DSB doesn't require a plenum to do nitrification. This thread has some notes I wrote on the topic:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=803686

great notes as usual --thanks again

Do you have anything on refugiums---esp flow rates--keeping copopods vs biological filtration advantages

 

[bertoni]

No, I don't really have much information on that. I suspect a fairly low flow rate is fine, though. I ran about 140 gph through my 20g refugium, which seemed fine.

 

[Aquarist007]

<a href=showthread.php?s=&postid=10444396#post10444396 target=_blank>Originally posted</a> by bertoni
No, I don't really have much information on that. I suspect a fairly low flow rate is fine, though. I ran about 140 gph through my 20g refugium, which seemed fine.

I wonder if I need to add baffles---here is my setup --just basically an open refugium that drains slowly into the sump

 

[bertoni]

Looks fine to me.