DSB w vs w/o Plenum

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Toolio

Toolio

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Joined
Mar 22, 2005
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Location
Detroit, Mi
Howdy all. Looking for some feedback on this. I am starting another 135 gallon and definately wanna go with DSB. My other tanks have DSB's with plenums (actually more like UG filters as per GARF recommendations...). I love the DSB's but have a constant problem with pH. Mine in all tanks always stays at 8.05-8.10, even adding buffer every day. Not sure if this is due to the rapidization ( :) ) of the nitrogen cycling due to UG setup. GARF said to take powereads off risers when nitrate, nitrite, ammonia all=zero. But upon doing that all tanks crash ( Amm=.50 Nit=1.0 Nitrate=40.)immediately.
Question is, does anyone think this is due to the UG setup or should I remove Powerheads and be patient, or setup just plenum with DSB in new 135.
Questions galore....... Any feedback is greatly welcomed. :confused:
 
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the plenum/UG plate is useless in hobby applications IMO

And the most common handicap to DSBs is a lack of adequate waterflow. This is one of the biggest limitations to the methodology. With enough flow, they work fabulously... and without it they do indeed become nutrient sinks over time. Its really that simple. If you have slow or weak flow spots in the tank (any tank with substrate really), then solids will accumulate over time... and that is a problem.

There are many fine threads on DSBs on this and other message boards. You can see the pros and cons of both sides... but do realize that it is a heated debate, and not everything claimed by either side is necessarily true ;) Just gather a consensus for yourself. FWIW... I detail my take on the matter at great length in "Reef Invertebrates" in the live sand and refugium chapters :)
 
I hear ya guys. BTW, I am trying to become a farmer and have 10 or so tanks going now. My plugs are doing great, I almost cannot get rid of em fast enough. I probably will go with a DSB 5" with no plenum then. With adequate flow and no dead zones, do you guys think this is acceptable to raise mass plugs? So far, my best plug tanks have been UG style 5"DSB. My worst is my first 3 (3-4" crushed coral ion bare bottom with low flow. Can you say NITRATES!!!!) :) There are sooo many different opinions on what setup is ideal..... I guess it's whatever works for each individual. I just cannot figure out my pH problem, although I know it is only in tanks with the UG/Plenum/DSB. I do have tons of powerheads in those tanks with some ( i suppose) dead zones. All those tanks were started with base Tuffa instead of LR. Could this be a problem? Ex..55 gallon, 1" UG plate with 1 riser, 665 gph PH on riser, 3 400 gph aquaclear PH, Aquaclear 500 HOB with carbon. 100 lbs Carib Sea aragonite reef grade sand, 20 lbs live sand. Ammonia, Nitrite, Nitrate=0. pH=8.10. Calcium =400, Alk=3.5-4.0.
Thanks guys.
 
I use DSBs in all my frag/growout tanks. 6-8" in most... towards 12" deep in very large pools. Dick Perrin of Tropicorium has used even more sand then me, at deeper depths and for many more years. With skilled care, you can reap some fab benefits with DSBs... I just am careful about recommending them to newbies.
 
I would recommend " Live Sand Secrets " by Bob Goemans. This publication is put out by Marc Weiss companies. There is a second revised edition, that seems to be a little more thought out, in my openion. I am interested in a discussion on this book. So let me know what you think. Please. Have fun!!!
 
I had a DSB with the plenum and it was nothing but problems. I took out the plenum and left a shallow SB and the tank params are perfect and have been since the change. I do have some dead spots but siphoning helps that. HTH?
 
do consider that you removed the symptom (substrate that suffered with inadequate water flow) and not the problem (inadequate water flow).

The DSB was not the problem... its application was. This is THE biggest problem with deep sand beds.
 
Angel...

was your plenum an active one like the one described in my link?

MikeS
 
MikeS said:
Angel...

was your plenum an active one like the one described in my link?

MikeS
Click to expand...

I used the undergravel filter with the additional layer of mesh as suggested by GARF. I used the Powerheads and riser tubes to get the water moving as suggested then took them off after about a month. Worked great for a while then I started having troubles. Don't get me wrong I like the DSB b ut I don't like the plenum. Whne I set up the new tank I will have the front of the tank with sand and the back behind the rock BB. Seen this and it looked like a neat idea. Will try it and see.
 
anthony, i have heard of people having success with reverse flow undergravels and dsb's. would you be able to tell me the pros and cons of such a setup and what the proper flows with or without one is on a dsb?
 
hmmm...just my $.02....but a reverse flow UGF under a DSB would introduce way too much oxygenated water into the sand, sending the anerobic bacteria responsible for nitrate reduction into dormancy, thus effectively shutting down the nitrate reducing abilities of the sand bed (which IMO is the main reason to use one in the first place)...

The active plenum we describe in our linked thread above has only periodic introduction of oxygenated water into the lower levels of the DSB, thus giving the anerobic bacteria plenty of time to recover and begin fixing nitrate again...

MikeS
 
agreed... I don't like the concept of reverse flow DSB. Unnatural and bizarre to me. I can see no practical advantages. Pumping raw water underneath to inaccessible areas is a bad idea... and prefiltering it is even worse IMO. Silliness.
 
Mike.s I Read Through All 25 Pages Of The Plenum System Design. Looked Pretty Cool.reading Through I Thought Of A Similiar Design. When The Actual Test Was Done, Mojo Ended Up Cutting The Top Off Of The Plenum. This Was Done To Get It To Work, Without Leaving Piles Of Detritus On The Top Of It. I Thought That If You Could Enclose The Bottom Of The Plenum Design You Could Then Use Acrylic Slides On The Top. This Would Do Two Things. One Remove The Detritus From The Top And Two You Could Close The Slides To Pump Out The Water Having No Back Flush Effect At All. You Can Then Crack Open The Slides To Pull Some Of The Solids Through. I Will See If I Can Make Up A Pic For You To See And Critic Me. I Was Just Curious To The Reverse Flow Undergravel, Hearing People Have Success With Them Always Makes Me Wonder. My Tank Is A Bare Bottom....
 
you would have to add some supports for the egg crate...
 
by prefiltering I mean that as a solution to the horrible notion of pumping raw solids/particulates under a reverse flow DSB... the alternative is worse: prefiltering those solids will not only make you a slave to a mechanical filter that needs serviced almost daily (for fear of it becoming a nitrate factory), but also the very act of prefiltering said solids is robbing your filter feeders of feeding opportunities. The reverse flow method is a miserable notion all ways around.

Instead... with a normal DSB or barebottomed tank... strong water flow can keep particulates in suspension for recycling (of nutrients) by prolonged feeding opportunities by the many filter feeders in the tank... or the suspended solids are at least better exported by skimmers, for example, which wholly remove the matter from the system (degrading int he skimmer cup does not affect water quality like a prefilter would/does).

I'm not sure if I'm being too wordy again... or if I made it clear :p Do holler at me if the former ;)
 
Ok, I got it now... :D

Reverse flow through the DSB is obvioulsy a bad idea...how about the notion of the active plenum we described? Only a reletively small amount of water would be drawn out of the plenum every few months or so, helping to remove some of the nutrient buildup in the sandbed...the rest of the time it would act as a plain old DSB/passive plenum system...

MikeS
 
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