To Plenum and or not to Plenum

Dive_Master · 02-13-2002, 11:14 AM

I am considering setting up a plenum in my new tank. I've read that it works well in reducing Nitrates, but alson can cause a lot of problems if the substrate is too thick and Oxygen level falls below the acceptable range (forgot the range, I think it is less than 0.5). If the oxygen levels fall below this point, Hydrogen sulfide is created which is extremely deadly to fish and corals.

Sounds like a big risk! If it is true.

Does anyone have experience with using a plenum? Are there are signinfcant benefits to using the plenum for reducing Nitrates.

Is it better to create a really deep substrate ot not use one at all to minimize nitrates.

If I do not use one at all, the bottom of the tank will evantually be covered with coraline algae so it will not look bad, but it will give me the chance to contoll the water chemistry with more ease.

Rin · 02-13-2002, 12:10 PM

I've only heard about the H2S problem but I've never heard any credible stories about a tank crash that can be blamed by it.

Bacteria will form to deal with any gradual buildup of H2S so I wouldn't be concerned about a plenum for that particular reason. A dsb can form H2S for exactly the same reasons.

To me a DSB is easier to do than a plenum and they both perform the same function. A DSB will give you more fauna diversity, too.

hcp28 · 02-13-2002, 12:10 PM

I'd much prefer a DSB over a plenum any old day, but in my experience I've found plenums to have the tendancy to be short lived, well in a cosmic sort of way...

They do tend to break down suddenly and unexpectedly and what you have are nitrates and God knows what released into your system suddenly, causing a possible crash etc... of course that can be said for any system. I'd say if you have to go with no plenum and maybe fill a refugium with a DSB if you can. I just find Plenums tricky to set up and whne you have fish digging in the sand bed they can really mess it up, JMO hope this helps.

Henry

Dive_Master · 02-13-2002, 05:21 PM

How deep should it be. I have 4 inches in my fish-only tank and the nitrates are pretty high. I had them at 80 mg/l.

hcp28 · 02-13-2002, 10:25 PM

The deeper the better, but let me think the minimal recomondation was what 6-8 inches? that can't be right can it? I can't remember I think you would be fine if you added an inch or two slowly so as not to kill your existing fauna. HTH

Henry

David · 02-14-2002, 01:03 AM

Dive_Master- I have two tanks with plenums, a 125 and a 37. Both have been set up for over a year and I have never had measurable nitrates in either tank. I set them up in strict accordance with the design specified by Bob Goems. You are going to lose about 6" of tank so it only makes sense (to me) to do it with a very tall tank. I have never tried dsb but everything I read tells me it works just as well. Of course there are many factors that effect the success or failure of each aquarium system, I keep a very heavy macro algae growth so maybe that accounts for the low nitrates, uhhh... dunno.

Anyway I will give you give you one tip, if you go with a plenum in a glass tank with an "open bottom" or "frame" type stand, paint the bottom (outside) black. The last thing you want is light under the plenum. Water + nutrients+ light= ohhhh noooooooooooo!!!!

02-13-2002, 11:14 AM	#1
Dive_Master Citizen Join Date: Mar 2001 Location: Chicago, IL Posts: 214	To Plenum and or not to Plenum I am considering setting up a plenum in my new tank. I've read that it works well in reducing Nitrates, but alson can cause a lot of problems if the substrate is too thick and Oxygen level falls below the acceptable range (forgot the range, I think it is less than 0.5). If the oxygen levels fall below this point, Hydrogen sulfide is created which is extremely deadly to fish and corals. Sounds like a big risk! If it is true. Does anyone have experience with using a plenum? Are there are signinfcant benefits to using the plenum for reducing Nitrates. Is it better to create a really deep substrate ot not use one at all to minimize nitrates. If I do not use one at all, the bottom of the tank will evantually be covered with coraline algae so it will not look bad, but it will give me the chance to contoll the water chemistry with more ease.

02-13-2002, 12:10 PM	#2
Rin Mayor Join Date: Dec 2000 Location: Leesburg, GA Posts: 774	I've only heard about the H2S problem but I've never heard any credible stories about a tank crash that can be blamed by it. Bacteria will form to deal with any gradual buildup of H2S so I wouldn't be concerned about a plenum for that particular reason. A dsb can form H2S for exactly the same reasons. To me a DSB is easier to do than a plenum and they both perform the same function. A DSB will give you more fauna diversity, too. __________________ -Todd

02-13-2002, 12:10 PM	#3
hcp28 Evil Czar Join Date: Sep 2000 Location: New York, NY Posts: 1,001	I'd much prefer a DSB over a plenum any old day, but in my experience I've found plenums to have the tendancy to be short lived, well in a cosmic sort of way... They do tend to break down suddenly and unexpectedly and what you have are nitrates and God knows what released into your system suddenly, causing a possible crash etc... of course that can be said for any system. I'd say if you have to go with no plenum and maybe fill a refugium with a DSB if you can. I just find Plenums tricky to set up and whne you have fish digging in the sand bed they can really mess it up, JMO hope this helps. Henry __________________ Tragedy is when I cut my finger. Comedy is when you fall down an open manhole and die. -Mel Brooks

02-13-2002, 10:25 PM	#5
hcp28 Evil Czar Join Date: Sep 2000 Location: New York, NY Posts: 1,001	The deeper the better, but let me think the minimal recomondation was what 6-8 inches? that can't be right can it? I can't remember I think you would be fine if you added an inch or two slowly so as not to kill your existing fauna. HTH Henry __________________ Tragedy is when I cut my finger. Comedy is when you fall down an open manhole and die. -Mel Brooks

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02-13-2002, 05:21 PM	#4
Dive_Master Citizen Join Date: Mar 2001 Location: Chicago, IL Posts: 214	How deep should it be. I have 4 inches in my fish-only tank and the nitrates are pretty high. I had them at 80 mg/l.

02-14-2002, 01:03 AM	#6
David Citizen Join Date: Jul 2001 Location: San Diego Posts: 210	Dive_Master- I have two tanks with plenums, a 125 and a 37. Both have been set up for over a year and I have never had measurable nitrates in either tank. I set them up in strict accordance with the design specified by Bob Goems. You are going to lose about 6" of tank so it only makes sense (to me) to do it with a very tall tank. I have never tried dsb but everything I read tells me it works just as well. Of course there are many factors that effect the success or failure of each aquarium system, I keep a very heavy macro algae growth so maybe that accounts for the low nitrates, uhhh... dunno. Anyway I will give you give you one tip, if you go with a plenum in a glass tank with an "open bottom" or "frame" type stand, paint the bottom (outside) black. The last thing you want is light under the plenum. Water + nutrients+ light= ohhhh noooooooooooo!!!!

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