Plenums and the wasting "option"

[barryhc]

Ok folks, were going to take shot here, at removing nitrate of course, and P to be sure, and whatever other "nasties" that we can.

I am promoting wasting plenums here, and It will be said, "that has already been tried". Yep, quite a few years ago, and no reported long term success.

The intent here is to develop a method that will allow various nutrients and compounds to be removed from a substrate, in a reef aquarium.

That substrate is subject to definition, and its particle size, depth and layering, are not likely to conform to any current or past "models" for "DSB", or "plenum".

This thread is for those who do want to run a substrate of one type or another in their reef aquarium, for whatever reason, and different reasons may require different specific solutions.

Let's start, and continue to enjoy our reef keeping hobby!

Thanks > barryhc

 

[kbmdale]

Step one: how to get the soup(P and N) out of the pot(DSB) without removing the lid (not disturbing the aerobic and anaerobic layers).

You definately have to have something in place that pulls from the bottom. A well designed manifold that has even pull across the whole bottom of the bed. The variables would be Flow rate(gph it will take to get even pull), Flow Cycle (how long can you pull without pulling o2 into the anaerobic area), Flow Frequency(How often should can it be done without hindering the DSB's process)...

should we start there?

 

[barryhc]

Yes exactly, that is where I have put most of my efforts so far.

There might end up being a "layering camp" and a "nonlayering camp" as a result of this investigation, and that is quite fine by me.

I am going to be in the "layering camp" for quite some time, primarily because of the "critters" that I want to keep.

Some people who are not interested in "substrate critters" may want to opt for no layering, although, I think layering is going to be valuable in both cases, just done differently.

The flow, as I said, I have a handle on this, and you are very close with the 1/4" depth per "draw" that you mentioned, probably.

It might be valuable here to develop a model that works for controlling the various "oxygenated zones" in such a fashion that the substrate is maintainable ( or controlable ), with somewhat less regard for "critters" initially.

Of course, we are also going to be wasting a good portion of "something" in the "effluent". How we "control" the "downflow" is crucial to properly managing the bacterial and chemical processes that occur within this substrate.

It is the depth of these processes that we don't know enough about, and the model that we end up with even initially, is not going to be something that any studies have been done on.

However, the "Biological Phosphorous Reemoval" thread that I mentioned previously, may be much more valuable than it would initially appear.

I have been promoting what I call "High Frequency Plenum Wasting", and it is the "small draw volume" at "high flow", that is necessary to keep the flow "balanced" across the substrate area ( and its depth ). Doing so "'often" ( High Frequency ) is what will simulate a "continuous" flow.

It won't be continuous, and this is why the above "BRP" thread may be so valuable.

I hope this hasn't been too "longwinded", let me know . . . . > barryhc

 

[barryhc]

I can get very much more specific about the flow ( how to develop it mechanicly ), whenever you like, I'm just setting up the information extra carefully here at the beginning, so that we don't get "derailed".

It isn't a problem, but we do have to carefully define what we are trying to accomplish here, and without a model that at least attempts to address the "oxygen gradation" and bacterial activity within that, we would just be "blowing smoke".

Just the same, if you would like to see the "math" so to speak, regarding the "flow", give me a "foorprint" ( substrate area ) to work with, and I will develop some flow information that is specific to that "tank substrate area".

Thanks for keeping it "moving" Kris, > barryhc

 

[kbmdale]

I have a 29g with a foot print of 30x12. That should be a good starting point.

Lets start with the lowest level in the tank the bottom and work from there.

The manifold: How many pull points should there be coming from the manifold to effectively move a burst or water (1/8" drop)?

One in each corner? or one in the middle of the back?

How would the manifold need to be laid out to get even pull..

Do you have any drawings Barry? I can draw something out if I have some idea of hole placement and flow cordination.

I was intending to use 1/2 OD PVC with the holes covered by sections of filter bag cut to fit the area over the hole.

 

[stugray]

barryhc,

1 - nice avatar.

2 - I installed a plenum just as in the "DSB heresy" thread. I believe in the pvc plenum with lots of holes and wrapped in landscaping fabric. Pics of my plenum are in my gallery. The plenum is in my sump only, not my display. The "layered sand" is 6-8" deep. I havent attempted to draw anything through it yet, but I am getting ready ( sump is only about 1-1/2 months old ).

I will be following this thread closely.

Stu

 

[kbmdale]

stugray

sounds great let us know what you get when you bleed it off. Are you going to test the sludge to see if what you're getting out? Are you going to take readings before you purge and regularly after you purge, this is VERY useful info to where this thread is going..

What grains of sand did you use at what levels? Any pertinent info on the setup would be GREAT.

thanks,
Kris:bum:

 

[barryhc]

Alrighty then.

I think that you can do a pretty good job on a smaller tank which yours is, with a single draw point, but being were only going to use one, let's "pull" from the center of the tank. This is not really difficult at all, and is probably the preferred for "smaller" areas.

Keep in mind here that eventually, all "piping" is going to end up with one pipe, right? So, you can accomplish the flow ( or vacuum ) gradation in many different ways.

My favorite, is to "oversize" the "feeder tubes" ( your 1/2"
I. D. PVC ). The 1/2" I.D. PVC is suffeciently oversized for most applications, and, is also a factor in the "plenum space". I,m currently sticking with the Plenum idea here myself, I believe it makes a difference. I'm not positive that this difference is good, but I think it is, and we'll have to discuss that further later, or this will become a 25 page reply!

Kris, your 30 X 12 tank has an area of 360 sq. in. outside, probably 340 sq. in. "inside".

Go to www.JoshMadison.com if you don't yet have "convert.exe"

231 cubic inches = 1 gallon. 231/340 says that you have 1 Gal. of water for each .680" ( 11/16" ) of vertical water column in your tank.

Let's say you want to "draw" 1/8" of "vertical water column", each time that you "draw". So, .125/.680 = .184 gal. that you will "draw" each time.

Ok, now I reccomend that as far as flow goes, you need "high flow", which is subjective, but let's just put in an example here.

Let's say you've decided to go with 90 gph flow through the plenum during "wasting". I reccomend that you restrict the flow by 50% in order to cause flow to be "balanced" across the substrate area. This relates to the aforementioned "manifold oversizing".

Let's arbitrairly pick a 3/64" dia. hole > .047" dia. Your PVC I.D. is .500"dia. Ok, now let's just calm down here, your 7th grade teenager can do this, just ask him/her.

So, .500"squared divided by .047"squared = 113 holes. That's not so bad. Then there is the "manifold, but it isn't much different than the "standard plenum" described by "Goemans".

This math can be worked back and forth to solve starting from different criteria.

I could write a "real formula", but everyone would "drop dead" immediately, besides, we still have to determine the recovery rate of the bacteria after "we" draw" this 1/8" of water, right?

Some of this "recovery rate" stuff, will have to be determined by experiment, but I refer again, to the "BPR" thread. This is going to give us a place to guess from.

So, what's next? Thanks > barryhc

 

[barryhc]

Hey Stu, I love your avatar, Geeze, I'm jealous, really!

I haven't wasted mine either, but I'm quite certian that "we" can do something with this, and we are right now.

Thanks, > barryhc

 

[barryhc]

Heh Stu, nice pictures, and lots of effort on your part in general too!

Please consider this, understanding my best intentions here.

It appears that your "feeder tubes" are WAY TOO FAR APART!

I really think this may have had something to do with LDRHawkes' having given up on this "system".

"Balanced flow" means "over the entire substrate area" and I really believe that the "feeder tubes" need to be "crammed in very tightly".

I don't think that you were given a good example, and these things "do happen".

Please stay with us here, and throw in the "input" as well.

Visit us again, "it's all good" > barryhc

 

[kbmdale]

Let me make some drawings of a few manifold layouts. I have some unconventional ideas I think might be useful here...

I'm working on it now.

I know a 29g is not a very big test system but Its empty and should be cost effecient for testing..agreed?

 

[kbmdale]

Barry do we agree here that the bottom 1" of sand bed is the part we are looking to purge?I feel that thats the point that the build up starts, so thats the point that needs fitlering to avoid the buildup and allow the upper sandbed to continue its processing.

 

[barryhc]

I have Cad drawings of mine, but I haven't got the "gully-dern" conversion thing happening yet.

Exactamundo on the 29 gal. ! . . . And I don't think it is the least bit too small to draw conclusions from either. We are doing this to put together a system for "reef keepers", right?

What size tanks do reef keepers have, heh?

Kbmdale:

Barry do we agree here that the bottom 1" of sand bed is the part we are looking to purge?I feel that thats the point that the build up starts, so thats the point that needs fitlering to avoid the buildup and allow the upper sandbed to continue its processing.

Whoa! Let's be very careful here. I agree that the bottom 1" is where we start "building the system", but, let's be careful here.

The area ( or depth zone ) that we waste needs to contain the nutrients and compounds that we are interested in wasting, agreed?

It is our job here to determine where these nutrients exist in a substrate model, and how we modify the "water column flow" and the "substrate model", in order to achieve our objectives.

Please review posts #1,3,5, and 7 in this thread( even just for 5 min. in total ), and respond to 3 or 4 items that I have proposed as being important to this investigation, so that we can proceed on some kind of "even keel" here.

If we squirt ahead too fast, we will lose a lot of what we are trying to accomplish. I have considered your posts that I have read ( on other threads ), and that is very, very many posts.

I trust you, so don't let me perturb you unreasonably here, but I need the feedback in order to answer your questions accurately, and I go to consideranle lengths to do just that!

You are on the right track ( no doubt ), and you are really "right on" here, but I don't care to repeat myself a lot, and you might be able to help me here.

Now, the particle size ( or grain size ). as well as the depth of the substrate bed, including any specific "scheme" of layering is going to determine at what depth these bacterial-chemical reactions occur.

Further, the "draw" frequency and volume ( duration ) are crucial to success with this system., and also effect this "depth".

We have to be designing this system to create and or accomodate these processes and control the depth at which they occur, so that we can "waste" the "things" that we want to waste.

We are also looking to improve the the "diffusion" that occurs near the substrate surface and back into the "water column".

Yes, all of this is entirely experimental, at this point, and I do apologize to you Kris, for getting so windy "again".

The shorter answer is that I would like to see the bottom 1" and the plenum after that, be the area where the "buildup starts".

I,m not trying to filter it though, just "waste it"!

And yes, then we can allow that "upper substrate" to continue its processing.

Actually, I happen to be leaning towards the "somewhat sandbed like" upper substrate version, that you appear to prefer. I think I do as well.

If we do any good here, it is going to take a while, but it is certianly worth it. Many people are likely to become involved in this thread, and if we don't wan't it to dissolve into a "war" we should be fairly concise.

If you will respond to answers that I have given previously, my answers will become very short indeed.

Thanks again > barryhc

 

[barryhc]

Ok, I'll try a different approach here. The "buildup" only starts there, if we arrange to "put it' there. This my point. Let's figure out how to put it there, and then "waste it".

Let's figure out how to put it there, with a substrate at the surface that we happen to prefer or enjoy. Maybe even for the benefit of the "critters" if that's what "we're" into, or not. if not.

I hope that's better, I have to apologize sometimes for being "anal", or whatever.

Thanks again, really! > barryhc

 

[kbmdale]

Ok . I didn't mean thst was the main goal of the system. Just the goal I was trying to accomplish in the first layer. To remove the Waste that settles deep within the bed. There are many many variables that will be brought into play and multiple other goals that will need to be met before the system will be successful..



Here is a quick little concept for a manifold. Now its open for all input, change, or redesign that might be needed to accomplish its goal, so I am not 100% sold on it, just a starting point.

the red lines represent the intake holes.

the idea of it being away from the sides was so that nothing couls be trapped between the wall of the tank and the intake itself.

This was just drawn up quickly in adobe. I have access to solid edge and can make a 3-D model with a little help from a drafting friend from work..

whatcha think?

 

[barryhc]

Well it's not bad at all, and a definite improvement over the "Hawke" design.

Try putting a "central intake" at the center of the tank, it really isn't difficult at all, just move your "rear tee" forward, to the center, then run a "line" from there to the left and to the right.

Run "legs, or "feeder tubes"from the center", towards you and away from you, with caps on the ends.

This keeps all extremity distances relatively short, and evenly balanced.

You could use reducing "manifold dias." to balance flow, or even drill larger holes as you get farther away from the "center" or "draw" point. The "oversized manifold with restricted flow" method is easier.

You have not asked about the "flow restriction" that I explained previously. You will be asking questions shortly that require that as part of the answer. It is absolutely crucial to the mechanical design of this system.

"Review-response"? Thanks for keeping "it up" > barryhc

 

[kbmdale]

That I will need help on. I am not quite sure how to get the flow to pull evenly through one outlet. Please elaborate

 

[barryhc]

You absolutely have to consider the "recovery rate", of the bacteria in this experiment, and tie that to the particle size, the depth of substrate, any layering that is going to be utilized, and then, of course, the Volume( "draw depth" ) and Frequency of the "draw".

If you don't, you are just throwing glass marbles at a "brick wall"!

If anyone tries to use this without considering the above, then they had best setup 20 tanks, with 2 sets of 5 tanks as controls, and then 5 versions with two tanks each as models.

It will all blow up certianly, even if you were to try the above.

Our only chance here is to consider these variables very carefully, and then take 1 or 2 shots at it. Even then, nobody will know that much for sure, until at least several years have gone by.

If we are lucky, or did our homework ahead of time, we may be able to report, that things are working smoothly.

Mr. Hawke claimed it was the greatest thing since sliced bread, and then gave up on it after 9 mos. or so. That is not going to happen to me.

Don't get me wrong, I started this thread, but "magic bullets" do not exist, and "plenum wasting" will not be one either.

Thanks to all, > barryhc

 

[kbmdale]

so as an "experiment" to try figure out a few variables like rate of pull and sand depths. For a starting point. What if I took a 5 gallon bucket, put a 1/2" piece PVC in the bottom that goes through the bottom. About 1/8" sticking up in the inside of the bottom. Then lay a layer or 4mm CC or Sand then screen then start with 8" of 1-3 mm sand on top of that.

Then I can put a gate valve at the end of the pvc and fill the bucket with water. See how long it takes the water to drain through the substrate with a gravity pull. I could play with the depths and record the rates.

Does that sound like a reasonable way of judging how the water level will drop pulling water through the substrate and the give us an idea of how easy or hard we will need to pull.

it wouldn't be an exact but an idea of what will happen.

 

[barryhc]

OK, but if you don't give some response to the previous posts, you will make my two little fingers bleed( the typing ones ).

If I start answering your questions without knowing if you understand the previous information, then we are doomed to a "cluster shuck" here.

I gave you about half of the "flow math" before, I cannot proceed without knowing if you understand that portion. Seriously.

Flow "durations" are going to last in the "range" of probably about 5 to15 seconds maximum, this is not arbitrary, it has to do with "bacteria recovery" times VS "Total Monthly Draw".

This "TMD", needs to be within the range of monthly water change volume, Unless of course you want to get silly with it.

Remember, we are talking ( thus far ) about throwing this stuff away.

Please bear with me here, but I cannot proceed without specific response to solutions that I have offered. I will explain it again as well, as long as you "specify" the portion that you are not comfortable with.

Let's go! > barryhc