Undergravel Filter, does anybody use them still?

scottnlisa

Member
I have a 30 gallon tank. I am currently running a millenium 3000 and Aquatech 100 for my filtering system. Does anybody still use undergravel filters? If so, would it benefit my tank?
 

scsinet

Active Member
I've never heard of them used for anything saltwater related.
For one thing, they destroy any benefit from the denitrating qualities of the sandbed. For another, it's doubtful they can support the weight of live rock, and for another, the airstones to drive them would cause microbubbles, though this can be mitigated by using a powerhead for (as it happens, the original application for which powerheads were intended) driving them.
For what a nice biowheel HOB costs, why bother?
 

bmkj02

Member
Undergravel Filter is for fresh water. I have one in my freshwater 55 gallon but dont on the saltwater tank
 

scopus tang

Active Member
Originally Posted by SCSInet
http:///forum/post/3162024
I've never heard of them used for anything saltwater related.
For one thing, they destroy any benefit from the denitrating qualities of the sandbed. For another, it's doubtful they can support the weight of live rock, and for another, the airstones to drive them would cause microbubbles, though this can be mitigated by using a powerhead for (as it happens, the original application for which powerheads were intended) driving them.
For what a nice biowheel HOB costs, why bother?
LOL, know I'm showing my age here, but the original salt tanks were all set up with CC over undergravel filters driven by powerheads (at least in this area). Course they were also kept with bleached corals (litorally) and short-lived fish.
As others said, wouldn't bother, although I have seen them used under a DSB as a Plenum.
 

posiden

Active Member
While they aren't the most popular, there are a couple of die hards that still run them. One comes to mind instantly. He is on the big site, Paul B. His tank is just about 40 years old. He has run an UGF from day one. Though he runs it in reverse. He is a great guy to talk to. His thread is huge. Anyway, here is a quote I copied from reef keeping mag from when they featured him.
“I took out the UG filter last year for a cleaning. I do that every 25 years whether it needs it or not.”
Link to the artical;
http://www.reefkeeping.com/joomla/in...zine/article/7
Here is another clipping,
" Although I have quite a few theories regarding this tank's success, I feel that a reverse-flow, slow running, undergravel filter is the main reason this tank has lasted successfully for four decades"
 

geoj

Active Member
I still use one in my QT
The others are right “they destroy any benefit from the denitrating qualities of the sandbed” so you cant rid the tank of nitrate with a Undergravel Filter.
What I get in my QT is the benefit of Ammonification and Nitrification. Ok the old way we did water changes to rid the nitrate, and being only one fish at a time in my QT does not need many water changes.. Also THE REDOX POTENTIAL is better from the added gas exchange.
Now for the salt creep I don’t fill the QT all the way up, I leave some room for the micro bubbles to spray harmlessly some salt creep will show up but its not to bad.
In the DT nope...
 

posiden

Active Member
Originally Posted by GeoJ
http:///forum/post/3162139
I still use one in my QT
The others are right “they destroy any benefit from the denitrating qualities of the sandbed” so you cant rid the tank of nitrate with a Undergravel Filter.
What I get in my QT is the benefit of Ammonification and Nitrification. Ok the old way we did water changes to rid the nitrate, and being only one fish at a time in my QT does not need many water changes.. Also THE REDOX POTENTIAL is better from the added gas exchange.
Now for the salt creep I don’t fill the QT all the way up, I leave some room for the micro bubbles to spray harmlessly some salt creep will show up but its not to bad.
In the DT nope...

Are you running it with an air stone?
Give the artical I linked to a read.
 

geoj

Active Member
Originally Posted by Posiden
http:///forum/post/3162484
Are you running it with an air stone?
Give the artical I linked to a read.
Yep, the standered undergravel filter, w/air line going down the stack to pull all waste down into my CC.
I give the article you linked to a glance.
“That undergravel filter was my second mistake. Not that an undergravel filter is detrimental in saltwater, but the way I was using it was not quite right. After about a year, the undergravel filter clogged, effectively stopping the nitrification process and causing undue stress on the fish.”
What he is saying here, is the way it was at the time. Nitrification is the conversion of ammonia to nitrates. He never got rid of nitrates it would build-up and he would do weekly water changes to keep that in line. But his ammonia and nitrite the deadly waste would be handled till the filter clogged.
So when the filter clogged it shifted to Anaerobic water so Denitrification started its the reduction of nitrates back into the largely inert nitrogen gas (N2) this would be good, completing the nitrogen cycle, but a little bug would produce hydrogen sulfide gas this gas would causing undue stress on the fish if in large amounts. And he lost most of his ammonia and nitrite reduction and these deadly waste would build and wipe out the tank.
The clog happened because there was heavy feeding of the tank and no Denitrification. It would still happen in a system with more feeding then the Denitrification can handle example over fed DSBs.
His reversing the flow would only give him more time “Old tank syndrome” took 2-3 years.
I get away with it in my QT because it is so under fed the pods and a very miner amount of Denitrification can handle it, I also check how much waste is under there by back blowing or taking it apart once a year.
Like I said before this would not be cool in a DT…
 

phil47952

New Member

Originally Posted by Posiden
http:///forum/post/3162131
While they aren't the most popular, there are a couple of die hards that still run them. One comes to mind instantly. He is on the big site, Paul B. His tank is just about 40 years old. He has run an UGF from day one. Though he runs it in reverse. He is a great guy to talk to. His thread is huge. Anyway, here is a quote I copied from reef keeping mag from when they featured him.
“I took out the UG filter last year for a cleaning. I do that every 25 years whether it needs it or not.”
Link to the artical;
http://www.reefkeeping.com/joomla/in...zine/article/7
Here is another clipping,
" Although I have quite a few theories regarding this tank's success, I feel that a reverse-flow, slow running, undergravel filter is the main reason this tank has lasted successfully for four decades"

Posiden, I've followed Paul's thread and anyone that thinks it can't be done, UGF in salt needs to follow your link to Pauls decades old setup. He has fish and corals that are 8 to 10 years old.
Phil
 
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