Opinions on Plenum's
- Thread starter jarre
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surfnturf
Member
Jarre,
The wet/dry system has fallen out of favor, many still use it, but really there isn't much of a point. The current thinking is the use of a deep sand bed (4-7 inches depending on who you ask) and 1-1.5 lbs per gallon of live rock with a good skimmer going. Most people do a DSB without a plenum, I couldn't really tell you that w/plenum is better than w/o, or vice versa. A real simple plenum setup would be to put an undergravel filter in with 4-5 inches of sand, with a powerhead on each uplift tube. Go through the cycling period, then remove the uplift tubes and cap the holes off. This gives you a Jaubertt plenum or NNR if you prefer to call it that. Anyway, plenum or no plenum, a DSB is really the way to go, bioballs and wet/dry's are nitrate factories, a DSB will consume nitrates, not produce them. I'm sure a boatload of people will jump all over what I said, so you should read what they have to say as well. Best of luck to you.
The wet/dry system has fallen out of favor, many still use it, but really there isn't much of a point. The current thinking is the use of a deep sand bed (4-7 inches depending on who you ask) and 1-1.5 lbs per gallon of live rock with a good skimmer going. Most people do a DSB without a plenum, I couldn't really tell you that w/plenum is better than w/o, or vice versa. A real simple plenum setup would be to put an undergravel filter in with 4-5 inches of sand, with a powerhead on each uplift tube. Go through the cycling period, then remove the uplift tubes and cap the holes off. This gives you a Jaubertt plenum or NNR if you prefer to call it that. Anyway, plenum or no plenum, a DSB is really the way to go, bioballs and wet/dry's are nitrate factories, a DSB will consume nitrates, not produce them. I'm sure a boatload of people will jump all over what I said, so you should read what they have to say as well. Best of luck to you.
jarre
Member
Thank you surfnturf and Bang Guy!! I have been leaning toward the DSB because if I error in setting up the Plenum disaster seems to be the conclusion. Since I've only had 5 months experience with salt safety may be the most prudent course of action.
Wanted to mention I read posts from both of you and have found them to be quite informative!! Bang Guy - Love the Fuge man!!!
Wanted to mention I read posts from both of you and have found them to be quite informative!! Bang Guy - Love the Fuge man!!!
wamp
Active Member
The wet/dry system has fallen out of favor,
I would not say that too loud...
I actually like the Wet/Dry. You use that in conjunction with LR and LS and you'll have no worries. IMO, they are one of the most efficent filters on the market.(not saying the Fluval is though, never liked them)
Cna't beat em' for the price..
I would not say that too loud...
I actually like the Wet/Dry. You use that in conjunction with LR and LS and you'll have no worries. IMO, they are one of the most efficent filters on the market.(not saying the Fluval is though, never liked them)
Cna't beat em' for the price..
surfnturf
Member
Wamp,
I know what you mean about "saying that too loud". I realize that quite a few people still use them, although I've never seen a "cheap" one, usually they are pretty complicated acrylic contraptions that go for a high price, at least around here. Wet/Dry filters are the most efficient way to convert Ammonia to nitrite to nitrate, but that is the end of the line as far as what they can do. It does seem a little more logical to get what you can out with a GOOD skimmer, then let the LR and LS (DSB) take care of the rest, either way you should never see ammonia or nitrites, but W/D by themselves (without a skimmer or esp DSB) only add to the nitrate problem. But, I would never ever argue with a shark! I am not argueing with you at all. With the incredible efficiency of a wet dry, it leaves me thinking about is the posibility that a good portion of the nutrients that would have been exported by the skimmer are converted to the end product of nitrate by a wet/dry before the skimmer even has a chance to do it's job. It's all theory, and maybe I've got a short circuit in my brain, but it makes sense to me. A wet/dry hands down is the most efficient biofilter available, but there is a caveat.
I know what you mean about "saying that too loud". I realize that quite a few people still use them, although I've never seen a "cheap" one, usually they are pretty complicated acrylic contraptions that go for a high price, at least around here. Wet/Dry filters are the most efficient way to convert Ammonia to nitrite to nitrate, but that is the end of the line as far as what they can do. It does seem a little more logical to get what you can out with a GOOD skimmer, then let the LR and LS (DSB) take care of the rest, either way you should never see ammonia or nitrites, but W/D by themselves (without a skimmer or esp DSB) only add to the nitrate problem. But, I would never ever argue with a shark! I am not argueing with you at all. With the incredible efficiency of a wet dry, it leaves me thinking about is the posibility that a good portion of the nutrients that would have been exported by the skimmer are converted to the end product of nitrate by a wet/dry before the skimmer even has a chance to do it's job. It's all theory, and maybe I've got a short circuit in my brain, but it makes sense to me. A wet/dry hands down is the most efficient biofilter available, but there is a caveat.
wamp
Active Member
but W/D by themselves (without a skimmer or esp DSB) only add to the nitrate problem
Common thought here but not quite accurate. They will not add to the problem, they just do nothing for it. They only house aerobic bacteria. This bacteria is responsible for the breakdown of ammonia and nitrites.
Anaerobic bacteria which is housed in DSB and DEEP within live rock is what converts nitrates into free nitrogen which escapes through the water column.
Now, stay with me here, With the use of a wet Dry, the water is oxygetad at a much higher rate vs. that with LR only. So, the amount of 02 going in allows the escape of other gases at a faster rate.
With the escape of these other gases helps speed the nitrogen cycle. So in conlusion, the Wet/Dry is the most efficent, IMO, on the market but as you stated it does need a little help.
For the money, think about my old tank. 180 gallon. You would need 180-220 lbs of live rock for a heavy bio-loaded tank, which most aquarists have. At 3$ a pound, that would be $540-660.
Most Wet/Drys on the market large enough for that tank are around 250-450$ with pump.
Not saying any of your statments are incorrect but they do have a very meaningfull role in this hobby. I would put them up against LR in the nitrogen cycle challenge any day. But, LR does have many more advantages. My suggestion to all is, why not have all 3?
A skimmer helps by removing dissolved organics before they have an oppertunity to become nitrate and other waste. IMO, there not a contributing factor much at all in the nitrogen cycle.
P.S. Don't be affraid to arguee.... Thats what all conversation is bassed on. If me and you thought alike, we would not be posting now
Common thought here but not quite accurate. They will not add to the problem, they just do nothing for it. They only house aerobic bacteria. This bacteria is responsible for the breakdown of ammonia and nitrites.
Anaerobic bacteria which is housed in DSB and DEEP within live rock is what converts nitrates into free nitrogen which escapes through the water column.
Now, stay with me here, With the use of a wet Dry, the water is oxygetad at a much higher rate vs. that with LR only. So, the amount of 02 going in allows the escape of other gases at a faster rate.
With the escape of these other gases helps speed the nitrogen cycle. So in conlusion, the Wet/Dry is the most efficent, IMO, on the market but as you stated it does need a little help.
For the money, think about my old tank. 180 gallon. You would need 180-220 lbs of live rock for a heavy bio-loaded tank, which most aquarists have. At 3$ a pound, that would be $540-660.
Most Wet/Drys on the market large enough for that tank are around 250-450$ with pump.
Not saying any of your statments are incorrect but they do have a very meaningfull role in this hobby. I would put them up against LR in the nitrogen cycle challenge any day. But, LR does have many more advantages. My suggestion to all is, why not have all 3?
A skimmer helps by removing dissolved organics before they have an oppertunity to become nitrate and other waste. IMO, there not a contributing factor much at all in the nitrogen cycle.
P.S. Don't be affraid to arguee.... Thats what all conversation is bassed on. If me and you thought alike, we would not be posting now
surfnturf
Member
Wamp, I really like the arguement of the W/D to reduce the amount of LR you would need in a tank, I never thought of it in that context. Denitrification value of LR I think is overestimated or at least overadvertised, it doesn't really do that much IMHO, the DSB certainly does though. Back to the subject of skimmers though, I'm not sure if I did a good job of presenting my thought. A skimmer will remove a certain percentage of DOCs before they can be further converted the final product of nitrate by biofiltration. What my thought was, or is, is that as the water passes through a w/d nearly all DOCs are converted to their end product of nitrate, it works at a very high rate, much faster than a skimmers ability to remove the DOCs before conversion. Conversion of these DOCs by LR and LS is somewhat efficient, but not nearly that of a w/d. So in theory, a skimmer could be used to remove all DOCs that it is capable of and the leftovers could be converted by the LR/LS with a lower potential for Nitrate accumulation. I think I read too much Goeman, Thiel, and Fedder stuff. Anyway Wamp, thanks for the conversation, I really like some of the ideas you presented, and I also realize that no idea is right or wrong, each situation is different, but it is a lot of fun to chat with someone like you.
wamp
Active Member
There is really no such thing as too efficent filtration.
Nitrate is actually one of the slowest to build up and also the slowest to be removed. So, this is where we differ, I think that no matter how well the wet/dry does it, it will hae no end affect on how a skimmer operates or how the nitrates build up.
Even though a Wet/Dry is effiencet, it's not that fast at converting.
Example:
It takes the average tank, about, 1 month to complete it's initial cycle. During that cycle, Ammonia rises...well you know the way it works....
Once your nitrites drop, It still takes a while for the nitrates to build. The will rise slowly over time and if left unchecked will really rocket if no routine maintance is done. Now, once they build up. How long does it take for them to natrually fall? Take all your bio-load of of the equation, How long For the DSB and skimmer to get rid of them all. I can tell you this from experiece... A while... So in conclusion, No matter how fast the filter, nitrates are still slow to rise and slow to convert, so I would not put the efficency , as other authors have, in this equation.
Nitrate is actually one of the slowest to build up and also the slowest to be removed. So, this is where we differ, I think that no matter how well the wet/dry does it, it will hae no end affect on how a skimmer operates or how the nitrates build up.
Even though a Wet/Dry is effiencet, it's not that fast at converting.
Example:
It takes the average tank, about, 1 month to complete it's initial cycle. During that cycle, Ammonia rises...well you know the way it works....
Once your nitrites drop, It still takes a while for the nitrates to build. The will rise slowly over time and if left unchecked will really rocket if no routine maintance is done. Now, once they build up. How long does it take for them to natrually fall? Take all your bio-load of of the equation, How long For the DSB and skimmer to get rid of them all. I can tell you this from experiece... A while... So in conclusion, No matter how fast the filter, nitrates are still slow to rise and slow to convert, so I would not put the efficency , as other authors have, in this equation.
frankl15207
Member
Thanks for the discussion. I do agree with Wamp on the benefits of wet/dry. Specifically their ability to oxygenate the water fully.
I've found a distinct difference in stability of water conditions with one vs. without one.
Back to the plenum question. No doubt as pointed out by Bang Guy that both work. I steered away from using one because I read that in areas with frequent power outtages they may leach toxic gases back into the water table. Outside of reading that, I've never seen anyone else have a problem with them.
I've found a distinct difference in stability of water conditions with one vs. without one.
Back to the plenum question. No doubt as pointed out by Bang Guy that both work. I steered away from using one because I read that in areas with frequent power outtages they may leach toxic gases back into the water table. Outside of reading that, I've never seen anyone else have a problem with them.
fshhub
Active Member
IMEO, the wet/dry, is a bit more old school, it does work and work well, but needs accompanyment to finish the job. and also COSTLY.
But still has its uses in many systems, although I do not like them, I do reccommend them in some instances.
As for the dsb vs plenum, the only thingI have against the plenum, is if anything happens, it is easier to remove/replace a dsb, and it is also easier to set up a dsb(althogh not difficult to set up the plenum). For those 2 reasons alone, i feel the plenum is outdated(for lack of a better term). Otherwise, they are equally efficient.
But still has its uses in many systems, although I do not like them, I do reccommend them in some instances.
As for the dsb vs plenum, the only thingI have against the plenum, is if anything happens, it is easier to remove/replace a dsb, and it is also easier to set up a dsb(althogh not difficult to set up the plenum). For those 2 reasons alone, i feel the plenum is outdated(for lack of a better term). Otherwise, they are equally efficient.
wamp
Active Member
Thin of a plenum as being an Under gravel filter with no flow at all under a Deep bed of sand.
In there, anaerobic bacteria is allowed to build up and denitrification can take place. They are said to be much faster at converting nitrates than a DSB but IMO they both do about the same job.
In there, anaerobic bacteria is allowed to build up and denitrification can take place. They are said to be much faster at converting nitrates than a DSB but IMO they both do about the same job.
gregzbobo
Member
I'm just getting back into setting up my tank after a 2 year hiatus, and have not really been able to keep up with new advances. It was my understanding that deep beds of sand harbor hydrogen sulfide bacteria (nasty black spots in sand) which produce hydrogen sulfide gas, has this changed? This is what I thought the plenums were supposed to do away with, allow deep beds of sand which do not harbor these nasty bacteria. If a deep sand bed truly IS better and easier than a NNR, then sign me up! I'm all about making things as easy as possible.
gregzbobo
Member
would I have to buy all live sand, or could I buy mostly dry and add some good live sand and a few pieces of live rock to get the rest of it going? Would I need to mix the live sand in with the dry stuff, or just stick it on top? Is it still a good idea to try to keep contact between the live rock and the substrate minimal, to cut down on dead spots and detritus buildup? Thanks for all the help so far. This is one of the best messageboards I've had the pleasure of being a member of.