DSB Heresy

[Scleractinian]

Do you think that it might be possible to treat a sandbed w/ a plenum and effluent drain as kind of a 'batch reactor' using this 'process', or that a VERY (dropwise) slow, consistent, flow might function like a denitrator coil, but be effective on PO4 as well?

Yes, that seems possible. I'm not sure how you'd decide what spped or frequency of draining was optimal. Maybe an ORP electrode stuck into the plenum, drain when it hits a certain low ORP threshold, and stop when it hits a higher threshold.

That would keep the plenum from getting too anoxic (if, indeed, that typically happens) and also prevent it from becoming too oxic, shutting down anoxic processes until the oxygen is depleted again.

Can you think of anyone familiar enough w/ the chemistry and microecology of marine sediments (and w/ an interest in captive reefs, of course) to offer guidance on such a thing?

When I was at the FSU lab at Sopchoppy, we used to make fun of the geeks and their Winogradsky Columns... guess I should have paid more attention to what was IN the sand, and not just on how much of it was moving where.

 

[BORECKI]

I want to backtrack a bit to the subject of compacting the sand bed and "chanelling".
At first I sugested using a eggcrate to install a pleniun under the DSB only to simplify the construction of the aperatus versus constructing a maze of pipes w/ holes each individualy capped with a small patch of fabric.
The responce I got was that because of the low head pressure anf flow there is no way to have even flow through all the sand bed and that places that by chance would get less flow would clog and force chanelling in other spots.
This is true
BUT ; The exact same thing will happen to a DSB served by a maze of pipes also. Only that in the latter the dead spots will be at the mid points between the holes. Each and every set of two holes will cause a dead spot to form at the mid point!
The only difference is that with a plenium one can fork the DSB to fluff it up easier than between the pipes.
Also ; If any one hole ever clogs up the two dead spots will merge and grow in size with no indication that anything is wrong!
If the whole idea is to revove phosphates than maybe the better option is still a DSB over a plenium where one can simply remove part of the sand every year or two in stages so that in time the whole bed is replaced. Another thing that was touched upon was the possability of the under sand pipes clogging due to lower pH in the stagnent water. That sounds like a possasble maintenence issue.
Boris.

 

[Shoestring Reefer]

Ok, for those who didn't see it, here is a VERY sucessful tank:

http://reefcentral.com/forums/showthread.php?s=&threadid=284686&highlight=Paul+B+30+Year+Old

 

[Scleractinian]

I want to backtrack a bit to the subject of compacting the sand bed and "chanelling".
At first I sugested using a eggcrate to install a pleniun under the DSB only to simplify the construction of the aperatus versus constructing a maze of pipes w/ holes each individualy capped with a small patch of fabric.
The responce I got was that because of the low head pressure anf flow there is no way to have even flow through all the sand bed and that places that by chance would get less flow would clog and force chanelling in other spots.
This is true
BUT ; The exact same thing will happen to a DSB served by a maze of pipes also. Only that in the latter the dead spots will be at the mid points between the holes. Each and every set of two holes will cause a dead spot to form at the mid point!
The only difference is that with a plenium one can fork the DSB to fluff it up easier than between the pipes.
Also ; If any one hole ever clogs up the two dead spots will merge and grow in size with no indication that anything is wrong!
If the whole idea is to revove phosphates than maybe the better option is still a DSB over a plenium where one can simply remove part of the sand every year or two in stages so that in time the whole bed is replaced. Another thing that was touched upon was the possability of the under sand pipes clogging due to lower pH in the stagnent water. That sounds like a possasble maintenence issue.
Boris.

This is why I dind't really like the pipe idea.

I realize that what I've been wondering about (a drilled plate, elevated off the tank bottom and seaed to the tank sides, w/ a simple drain from the plenum space, rather than from a network of pipes) doesn't fit either the Borecki (TM) or the CPW(TM!!!) model, but at this point I'm really more curious about the biology and chemistry than the plumbing.

Besides, at the flows I'm considering trying, plumbing won't matter much... I hope.

Hey!! I've invented my own process and apparatus! It's called the "Discrete Plenum with Drain", or DPD!

 

[BigDaddy]

I am in the midst of planning my new 280 reef and I have been debating the DSB, BB issue. This might be a nice solution. I hate the look of a BB tank, and I'm concerned about a possible nutrient sink in a DSB. I will continue to follow this closely, thanks for the thoughtful replies.

 

[Aged Salt]

Boris, yup, IME, eventually channeling WILL occur. If only back-flushing, areas of clumping in the bed will happen,irregardless of water changes,Bob

 

[Randy Holmes-Farley]

an you think of anyone familiar enough w/ the chemistry and microecology of marine sediments (and w/ an interest in captive reefs, of course) to offer guidance on such a thing?

Perhaps Ron Shimek.

 

[wld1783]

WOW at lot of thought here.

I will be moving in a year and using this move as a perfect opportunity to improve my current system.

I've read a lot of posts and it seems that a DSB has advantages but are also prone to crash. ldrhawke has a great idea for those who do not have the luxury of having a separate DSB Refrigium. Like investing money or combat, its a good idea and risk management that wins in the long run. This idea has low risk and I'm looking forward to future results.

For my system I'm still considering a DSB plenum refugium with a periodic drain on the plenum to remove the nasty stuff. For me this is low risk because it will be separate from the main system and can be removed/changed in the future if it becomes a problem.


Bill

 

[Shoestring Reefer]

Perhapse a different bed (not just grain size) would help, as well. The thread I linked to above is about a 30-year old tank with dolmite gravel.

Any other bed material thoughts?

 

[red rover]

ldrhawk....

Any updates?

 

[salt lick]

my summary of the CPW

my summary of the CPW

First a hats off to the CEO of Sewage for sharing his ideas. I think that removing the sulpher and acid from a potentially incomplete organic proccess is good thinking.

My first impression was that I had found balance in 'the Force'. I was following the thread thinking my new 225 gal will use this latest and greatest (400 lbs of southdown is waiting in the game room).

Do I DSB? BB? CPW? Oh the frustration! 10 yrs ago I had 2" of crushed coral in my 110 gallon reef, but removed it on the advice of Julian Sprung (FAMA). He said it was the cause of my algea blooms/ phosphate.

My next thought was that CPW is just doing a 30 gal/month water change on a system that holds 30 gallons (see below).
My estimate of total system volume is 30 gallons (does not take into account glass thickness). Actualy with dillution (1 gallon a day) its more like a 43% water exchange per month!

45 g tank (15" tall) with 5" sand 40 lbs rock and a 15 gal fuge:
tank (+45)
sand is about 10 gal, (-10)
rock/livestock is 15 gal, (-15)
15 gal fuge/sump/ half full is 8 gal (+8)
misc skimmer reactors (+2)

total vol = 30 gallons

The CPW method loses efficiency because of dilution but gains enormously by removing the worst byproduct water from the plenum. Then it struck me as just vaccuming the gravel bed from the bottom (dont know if thats better or not). It seems the CPW is a great way to do water change maintenance.

My next thought is Im not thrilled with a plenum contraption under the sand.

P.S. Please dont call me or my RC buddies idiots. Check your ego at the portal.

 

[Hawk72]

salt lick,

Where did you get 400 lbs. of southdown in Tehachapi?

The best option is to do what makes sense to you. This hobby is constantly changing. There is noway to say one method is better than the other (DSB,BB,CPW...). When I set mine up next month I am using a plenum with the wasting. I think that combines the best options for myself.

Jason

 

[llpoolej]

ldrhawke, I think it is a pretty cool idea. A french drain under the sand sucking out the nasty stuff. I agree with the larger size of the sand. Especially with your theories on it.

 

[DougSupreme]

I guess my main question is how to adopt this method. Is it simply to fill the bottom of your tank with as much piping as possible to evenly draw out the 'Liquor'? then it is simply a matter of siphoning out over the top of the tank? This sounds simple enough, my only concern is that I have about 300# of SD that i planned on using for my bed. Will this work ,or is the particle size too small? would frequent back flushing solve any compacting problems?

 

[ldrhawke]

ldrhawk....

Any updates?

Everything is very stable. I did run into one upsetting snag and error on my own part. My ORP probe was giving some high false read outs because it was dirty. When I soaked it in vinegar the ORP dropped almost 50 points, which was disappointing because now I am reading in the low and not the high 300's.

All of the ORP trend affects from my CPW are the same, I am just starting finishing lower than I figured. ORP has stabilized in the 320mv range.

I am going to do a 15% water change to see what if any affect it has on raising the ORP significantly over what I presently read. If it does raise ORP, it may be an indiction I should increase my present wasting rate. If it does not raise ORP it tells me water changes through CPW are about what they should be.

Lesson: If you are using an ORP meter, soak the probe in vinegar at least every few weeks. They will drift high if you don't.

 

[ldrhawke]

Re: my summary of the CPW

Re: my summary of the CPW

First a hats off to the CEO of Sewage for sharing his ideas. I think that removing the sulpher and acid from a potentially incomplete organic proccess is good thinking.

THANKS.......

My first impression was that I had found balance in 'the Force'. I was following the thread thinking my new 225 gal will use this latest and greatest (400 lbs of southdown is waiting in the game room).

Do I DSB? BB? CPW? Oh the frustration! 10 yrs ago I had 2" of crushed coral in my 110 gallon reef, but removed it on the advice of Julian Sprung (FAMA). He said it was the cause of my algea blooms/ phosphate.

.........THE SUBSTRATE DOES COLLECT PHOSPHATE. IT DOESN'T MAKE IT. HOPEFULLY CPW CAN CONTROL ITS BUILD UP AND USE IT AS A CONCENTRATOR POINT TO OUR ADVANTAGE. I DON'T HAVE ALL THE ANSWERS. I DO THINK CPW PUTS US ON THE RIGHT TRACK. TIME WILL TELL...........

My next thought was that CPW is just doing a 30 gal/month water change on a system that holds 30 gallons (see below).
My estimate of total system volume is 30 gallons (does not take into account glass thickness). Actualy with dillution (1 gallon a day) its more like a 43% water exchange per month!

45 g tank (15" tall) with 5" sand 40 lbs rock and a 15 gal fuge:
tank (+45)
sand is about 10 gal, (-10)
rock/livestock is 15 gal, (-15)
15 gal fuge/sump/ half full is 8 gal (+8)
misc skimmer reactors (+2)

total vol = 30 gallons

........SORRY DON'T FOLLOW ALL THE NUMBERS OR WHAT THE QUESTION IS?......

The CPW method loses efficiency because of dilution but gains enormously by removing the worst byproduct water from the plenum. Then it struck me as just vaccuming the gravel bed from the bottom (dont know if thats better or not). It seems the CPW is a great way to do water change maintenance.

My next thought is Im not thrilled with a plenum contraption under the sand.

P.S. Please dont call me or my RC buddies idiots. Check your ego at the portal.

.......IS THERE ANOTHER QUESTION HERE IDIOT?.......:lol:


........JUST KIDDING COULDN'T RESIST...

 

[ldrhawke]

I guess my main question is how to adopt this method. Is it simply to fill the bottom of your tank with as much piping as possible to evenly draw out the 'Liquor'? then it is simply a matter of siphoning out over the top of the tank? This sounds simple enough, my only concern is that I have about 300# of SD that i planned on using for my bed. Will this work ,or is the particle size too small? would frequent back flushing solve any compacting problems?

I would be concerned about using sugar sand. I believe it will plug and blind too easily, and cause maldistibution. That is not to say a finer grade filter cloth and shallower depth cannot be used to make it work. As more people use the CPW concept we may find modified different approaches will work, an possibly work better. At this point I believe a coarse grade agaronite is a safer approach.

 

[aqua_obs]

I've gone through some of what is happening here and hope "The Grand Poobah of Sewage" will lead us to a final answer! I say I've been on some of this path because I decomissioned an undergravel filter which used crushed coral. I decomissioned it because I had a hair algae problem. I thought I could do water changes from this spot because the UGF was built from a PVC network under a grating with window screen. I figured I'd get some of the nasty stuff out. My first water change smelled of elderberry wine (sulfur). That was over the summer and after performing this water change effort a few times I no longer get the sulfur smell. Maybe I've killed off the nitrate eating bacteria by pulling 5 gallons from a 60 gallon tank through the thin gravel bed. Nitrates seem to climb now every week despite a refugium with macro. I worry drlhawk that it is possible to reduce the number of nitrate eating bacteria through the bed by doing more and larger water changes? I'm currently going with your pint change method to see if my corals perk up. Again the sulfur smell has left my water as well, but I wonder if it ever comes back? In my tank, everything was doing really well after the under gravel water changes, but now the last few months things are going down hill and I'm not certain why. Additional point is my crush coral is only 1-1.5 inches thick. My CPW like method has been substantially different. I bet it's a good method, but like others, not a be all end all.

As a second suggestion to people who read RC and email. Don't read emotion into postings as it is usually a reflection more of your own state of mind more than the other persons.

Please keep up the good work dr-Hawk and others! thanks and one love brothers/ two loves for sisters!

 

[jrm01]

Brett & Chris,

I believe you are thinking of Tom Miller. He wrote a number of articles for MFM back in the late 90's one of which was titled "How To Set Up a Plenum and Plenum Siphon Network to Start a Handy Reef". It is in the April 1998 issue of MFM for those of you interested in taking a look at his thoughts.

Jeff

 

[H20ENG]

Thanks jrm01!
I knew it wasnt Tom Frakes, but couldnt remember a simple name like Miller
IIRC, He had the same general opinion that the plenum goes sour and is a nutrient sink. He didnt waste nearly what ldrhawke does, though. I bet he kept his nitrate reducers happy, though.

ldrhawke,
It seems you dont mind the nitrate reducers being over run with aerobic bacteria due to the volume of your water changes. Do you expect, or have you experienced, that the nitrates will stay very low with water changes only?
Chris