BB - Take 2

[mikester]

I've been running my tank BB/starboard for a couple of months now. For reasons I won't get into right now, I will be replacing the actual tank with a new one in a couple of weeks. At that point, I will redo my aquascaping, and I want to address a problem I've had with my first attempt at BB.

The biggest problem I've had is with detritus accumulating underneath the rocks. With nearly 2000 gph from my return, and a pair of Tunze Streams, I have great flow throughout the rest of the tank, but it's dead underneath the rocks.

Here's what I'm thinking about doing to correct this problem.

1) Make my aquascaping less dense and use either acrylic rods or a PVC structure to elevate the rocks slightly from the starboard.

2) Find a way to get some flow underneath the rocks. I have a few options here, but I'm leaning towards putting a couple of Maxijets underneath the rocks to blow the detritus out. I don't think I need a ton of flow under there - rather than try to keep the detritus in suspension, I'm thinking it would be better to just blow it toward the front or sides of the tank, where it can easily be siphoned out. So I just need a steady flow blowing out of the bottom of the rock structure.

I just wanted to get some feedback on this plan, and maybe some input from some of you guys on how you are keeping your barebottoms bare.

[tonkadawg]

when I upgrade to a larger tank, the plan is to go BB. What I want to do is build a pvc rock rack. Small holes will be drilled in it - like a spray bar. Then I will put a pump on one end of it and pump water through the rack. I think you get a big enough pump and drill the holes in the right places, you won't have any dead spots in your rock work.

[heyp]

I'm sorry for a little offtopic. I always read "starboard"? What is that? Can you explain - starboard - please?

[javajaws]

I've got holes in my tank for 2 closed loops. 1 with return outlets near the top...and 1 with return outlets a couple inches from the bottom. The plan is that the lower closed loop returns will keep stuff suspended off the bottom.

I'm also thinking of placing the live rock on top of clear acrylic rods about 1/2" high. I'm kind of worried about the rock structure sliding around on the StarBoard though if I do that. Maybe I could drill holes in the StarBoard and "pin" the rods and rock into place...

[javajaws]

I'm sorry for a little offtopic. I always read "starboard"? What is that? Can you explain - starboard - please?

StarBoard = cutting board type material used on the bottom of the tank to prevent rocks from cracking the glass.

[tonkadawg]

check RC - it is all over the place

[mikester]

I'm also thinking of placing the live rock on top of clear acrylic rods about 1/2" high. I'm kind of worried about the rock structure sliding around on the StarBoard though if I do that. Maybe I could drill holes in the StarBoard and "pin" the rods and rock into place...

That's exactly what I'm thinking of doing to prop the rock up. I read an article on using the rods to pin the rocks together, and yesterday on my weekly pilgrimage to Home Depot I picked up a wicked 12" long 3/8" drill bit and some fiberglass rods. I was thinking about making little "feet" for the base rocks to prop them up. They don't even have to be 1/2" - just enough so the rocks aren't touching the ground.

I think the rod method will work better than a PVC rack - it looks like it would be much easier to tweak the aquascaping and/or to remove part of it if I have to.

I also could add a closed loop if that works best. I still have my Ampmaster 3000 laying around - I guess I could spring for the new seals and use it for my closed loop pump. My tank is only viewable from the front and left sides, so I'm thinking I could run some black PVC spray bar along the back and right side blowing detritus out into the open.

Geez, if I go that route, I'll be looking at over 8000 gph in my 145g - 55x turnover.

[mesocosm]

Greetings All!

Make my aquascaping less dense and use either acrylic rods or a PVC structure to elevate the rocks slightly from the starboard.

Using acrylic rods and/or PVC support structures will allow you to create amazing formations ... much more functional than friction placement. Depending upon how you design things, the use of artificial support structures will also allow you to tear apart/rebuild your live rock structure and still retain the same design. You can also suspend structures midwater without any visible means of support ... I call them "anti-gravity rocks" ... another sign of my mental disintegration resulting from reef-keeping ... but, it's way cool ...

... the suspected rocks ... not my mental disintegration ...

http://www.theaquariumcenter.com/bio...tore90Reef.htm
This is a link to a pic of one of my earlier experiments. Not BB, but all of the live rock, except for a few small pieces used to hide small sections of the support structure, hovers at least 1/2" above the sand. The far-right polyp branch is actually a 18 lbs. piece of Acro-Fiji rock (... zoanthids all grown from 6, 2 inch frags ...) suspended against the back wall of the tank.

IME, acrylic rod segments epoxied into holes drilled into the rock allows much better flow under the rock ... PVC sections tend to deflect flow, and there's always concern regarding what's going with the water sheltered within the PVC section (... IME, drilling holes in the PVC never fully addressed my low flow/anoxic concerns, and the structural integrity of the PVC ... in terms of holding large weights ... was compromised ...).

Find a way to get some flow underneath the rocks ...

The acrylic rod segments that I've used have always allowed for more than adequate flow underneath the rock structure. With 20X - 25X turnover rate, only the heaviest particles accumulate and require manual removal.

I don't think I need a ton of flow under there - rather than try to keep the detritus in suspension, I'm thinking it would be better to just blow it toward the front or sides of the tank, where it can easily be siphoned out.

Sounds like an excellent strategy to me ... but don't be surprised when the heavier detritus particles DO NOT cooperate with your flow designs. But maybe it's just that my tank's detritus hated me personally ...

... I may never know ... .

I'm also thinking of placing the live rock on top of clear acrylic rods about 1/2" high.

IME, anything over 3/4" begins to look "too aesthetically compromised." By that I mean that the rod support "feet" become/"feel" VERY apparent. I've found that 1/2" to 3/4" allows for good flow without seeming too "unnatural" ... although clearly that's a relative thing ... JMO.

I'm kind of worried about the rock structure sliding around ...

Me too ... this was a definite concern. Up to a point, I am continually surprised at how stable a relatively small surface area of "acrylic rod feet" is, even while supporting relatively large weights of LR. The critical thing that I've experienced ... I'm not quite sure how to phrase this ... sorry ... has to do with the distance/angle that the LR weight is from the vertical center of gravity. The LR structure is very stable until it's angled/"leaned" just a little too far off of the center of gravity of the acrylic rod segments/"feet". I've resorted to stabilizing the top of the structure by using cable ties passed through holes drilled in the LR, and anchored/looped to the teeth in the built-in overflow (... or to pieces of PVC outside of the tank, anchored to the stand ...) to allow me to lean the rock structure beyond the "fall over and break the bottom of the tank" point. Oh yes, part of the thrill of aquascaping for me is ...

... the DANGER ... .

Maybe I could drill holes in the StarBoard and "pin" the rods and rock into place...

You probably won't need to drill through the starboard, and I would think that "friction fit" into 1/4" to 1/2" holes should work just fine holding everything in place. You should also be able to generate some interesting aquascape geometry with angled "anchorage" holes in the starboard.

Can't wait to see your tank's pictures!

JMO.
HTH.

[mikester]

There's some great tips here - keep them coming!

I would also like to just expand the topic to talk about the aquascaping in general. I'll describe the new tank as I understand it - we made several changes midstream, which were discussed over the phone with the builder, so I don't have a diagram, just a picture in my head (which I hope is the same thing the builder is picturing).

The tank is 48"x29"x24", which is the same as the tank it's replacing. The difference is that the current tank has a built-in filter that spans the entire back of the tank and takes up 5", so I really have a 48"x24" space to work with. The new tank, I will have the entire 29" depth to work with, which should be really nice. Midway along the back wall will be a short overflow box, ~ 16" wide by 4-5" deep. To cover the back wall and right side, he is constructing a series of black acrylic panels that will be removable for cleaning. Along the back, there will be a panel on either side of the overflow, and then a center panel that covers the overflow, and has angled mounts for my Tunze streams, so they will be mostly concealed.

OK, so that's a long-winded description, but the point is - I have 29" of depth to work with (except for around the overflow), so I'm trying to think of how to best utilize this extra space to get some nice aquascaping and provide good flow like we talked about before. My initial thought is to have the aquascaping short and flat, sort of like this:



I also like the look of this tank - not as flat, but still has that wide space and gradually builds up towards the back (but not too tall).



The other option I was considering was moving the overflow to the back right corner and build up the rocks high in that corner, then they would sweep out low and wide from there. This would provide an interesting viewing angle from both the front and left sides, which are the only viewable panes.

But I want to make sure that I will be able to manage the flow using either of these basic designs. Any thoughts?

[wasp]

Awesome looking tanks, but I just don't know how you'll get good flow under the rocks with a design like that, unless you used that rod thing.
For under rock flow, what I have that is working well is 3 powerful jets of water at the back pointing down. Goes down the back wall, and under the rocks to the front. There are two little "whirlpool" type areas near the front where all detritus collects for easy syphoning.

[mikester]

Tell me more about these jets, or even better would be pictures! I would love to do something that doesn't require a lot of plumbing underneath the rocks, if possible.

[javajaws]

BTW, usplastic sells PVC, HDPE, and Acrylic rods.

Does anybody know which would be less likely to crack under stress (for use horizontally supporting rock overhangs, etc.). I'm thinking the HDPE or PVC.

- Jason

[javajaws]

OK, so that's a long-winded description, but the point is - I have 29" of depth to work with

Sure, rub it in...

(except for around the overflow), so I'm trying to think of how to best utilize this extra space to get some nice aquascaping and provide good flow like we talked about before. My initial thought is to have the aquascaping short and flat, sort of like this:

I would think short and flat would be a bad thing...next to impossible to keep clean under there.

I would take advantage of those 29 inches. Build some vertical canyons that go from front to back at curvy angles. Make it more interesting to look at by requiring the viewer to move around slightly to see down the canyons. Only problem with such a design is getting enough current in and around the rocks.

[mesocosm]

Greetings All !

What follows is a demonstration of what can happen if you think about some of the things related to reef-keeping way too much. It's too late for me, but perhaps you can be saved ...

Disclaimer: I'm about to start ranting about technical "artistry" as it pertains to system design. I'm uncomfortable with such commentary, because the only "artistic perspective" that I am fit to comment on is my own. Anything else is arrogance, or worse ... so please cut me a little slack.

This rant is a little "out there". Apologies up front if it disrupts the flow of this thread. It's offered as "food for thought" only ... hopefully this will be useful ... perhaps it's just over-enthusiastic jibberish.

The thing is, there's a whole world of technical art "perspective stuff" that can be applied to reef system design, but rarely is ... although it might be interesting to note that folks like Takashi Amano utilize these concepts in every system they design ... with stunning results.

.. having said that ...

mikester,

... interesting viewing angle from both the front and left sides, which are the only viewable panes.

This part of the rant leads off in terms of maximizing what is presented through the viewable panes of your system, particularly the main pane. This gets a little obsessive ... okay, a lot obsessive ... but it's stuff that normally isn't discussed (... but IMO should be ...), let alone taken into consideration (... but IMO should be ...), when discussing reef system design.

FWIW ...

Other than the dimensions and geometry of the tank itself, where you choose to place your overflow box is the single most important design aspect which will define your system's visual focus, and the "flow" of your live rock architecture throughout your tank. And with it, the overall visual focus and the "flow" of eye movement as people observe the tank. How focus and eye movement occur largely determines how "comfortable" one "feels" when observing a marine system ... or any other artwork for that matter.

A "centered" overflow box will produce a symmetrical framework of viewing. The viewer's eye will naturally focus from that point, and move/radiate outward. The overall LR architecture should therefore begin with, and be designed around, this focus. A symmetrical framework is therefore limiting in terms of overall design. This is not necessarily a bad thing at all ... quite the contrary ... it just needs to be taken into account.

A "corner" overflow will produce an asymmetrical framework of viewing. The viewer's eye may, or may not focus on the overflow position. This context allows you to engineer a focus of your selection into your overall design. An asymmetric framework inherently contains a broader range of system design options.

My personal taste tends towards systems which "feel natural" ... whatever that means. To me it means designs which strongly "mimic" natural patterns. Natural patterns tend ... overwhelmingly ... to be asymmetric.

But there's a "rub" ... of course. All this babbling about symmetry, focus, focal, perspective, context ... yata yata yata ... gets implemented in the real world, where form & function collide with existing resources, space, time, and budget. The concept of a centered overflow with associated panels which obscure the Tunzes is most excellent ... I could easily see myself abandoning my asymmetric preferences for the kind of overall space & resource efficiency you're talking about. Way cool ... .

This is where I get a little more "out there" ...

You're probably familiar with a photographic concept referred to as "The Rule of Thirds" (ROT). My limited understanding of it ... despite Greg Rothschild's best efforts ... is that two dimensional fields, like pictures and the main viewing plane of an aquarium, can be divided into thirds. If lines were drawn, sectioning the field of view into thirds, the lines would represent "natural" focal points for most people. This concept can help to guide a designer of LR architecture. By placing LR, hence the specimens, in relationship to the lines corresponding to the ROT, the viewing of the specimens is naturally/automatically enhanced and highlighted. Something to consider ... .

The classical, more advanced variation of the ROT is referred to as "The Golden Rectangle." It can be used in both symmetric and asymmetric contexts. It's a formal perspective calculation used to maintain "realistic" proportion within two dimensional fields of view. It's something that is evidenced in the artwork of folks like Leonardo Da Vinci. It's still used today ... by folks like Takashi Amano. There's an actual method of calculation, but even my twisted ranting would not presume to include it unless asked. BTW, you'll need graph paper, a ruler, a protactor, a pencil, and some string to do it. Yeah, I actually go through it for clients who request it, or for projects whose budget demands it ... then again, I'm disturbingly interested in this topic ... go figure.

Enough ... I'll spare everyone my rantings on Fibionacci spirals ... back to the real world ...

The other option I was considering was moving the overflow to the back right corner and build up the rocks high in that corner, then they would sweep out low and wide from there. This would provide an interesting viewing angle from both the front and left sides, which are the only viewable panes.

Corner overflows sacrifice linear distance of the overflow box (... the perimeter of the top of a built-in overflow box ... does anyone know what it's really called? ... when I order systems from AAT and Lee Mar, we refer to it as "linear distance of the overflow" ...) in order to consume less space within the tank. Typically 12" of linear overflow area with a 1.5" bulkhead/drainpipe will easily accomodate 1000 GPH flow. Keep this in mind when you make your final overflow box dimensions ... others may use more precise ratios.

Any thoughts?

There was a point to this ranting ... if, instead of placing your overflow on the corner, you might consider centering it on one of the ROT lines. That way, you get full linear distance for the overflow box (... max flow vs. tank space consumed ...), AND you get to naturally hide the overflow within a natural focal point.

Awesome looking tanks ...

I agree, and yet ... they both seem to me to be very two dimensional ... very "triangular". They also don't seem to utilize system display volume very well ... but they're both VERY cool.

Something that may be absent in the LR architecture is light vs. shadow contrast. I don't see any flow from light, to dark, and back into light again. This transition can be important because it presents an illusion of added depth to the tank. Such built-in contrasts also make for full use of metal halide lighting characteristics (... penetrating single-point light sources ... multiple moire pattern "rippling" on different substrate/bottom surfaces ... etc ...).

I also don't see any natural focal points to influence fish movement (... no negative space utilization ...). It turns out that if you structure an open space between two regions of LR, with a full (or at least partial) overhang sheltering that open space, reef fish will naturally gravitate towards the space. They appear more comfortable "hanging out" in open spaces which are sheltered from above, and which provide escape niches to either side ... depending on the species, of course. Yes, LR architecture can/does greatly influence behavior. Such structures also generate transitions between light and shadow ... always good for a "feel" of added depth.

JMO ... they're great tanks.

... a lot of plumbing underneath the rocks ...

I've always found plumbing around/throughout LR structures to be problematic. Distribution of flow is never quite like what I hope/plan for, and I have an inherent distrust of the reliability of check valves ... perhaps what I really mean is paranoia. Any relatively powerful submersible pump, directed straight down the back wall of the tank (... hidden from view within the LR, of course ...) should be able to "flush out" detritus from behind the LR.

Sorry about the length ...

HTH.

[mesocosm]

Greetings All !

Does anybody know which would be less likely to crack under stress (for use horizontally supporting rock overhangs, etc.). I'm thinking the HDPE or PVC.

IME, 1/2" PVC is more than adequate, unless you're trying to support something massive, i.e. > 30 lb/ft . Larger diameter PVC can be used for heavier loads.

For horizontal structures, I use 1/2" PVC all the time. I've found that, for horizontal distances over 12", the issue is not strength, it's flex and "anchorage." PVC is typically superior to acrylic in those two areas.

BTW, I spray paint the PVC, prior to final insertion, with black Krylon Epoxy Enamel to make the PVC almost invisible. Both Krylon Epoxy Enamel, and Krylon Acrylic Enamel paints are inert in saltwater, after proper curing, of course.

While I prefer to use extruded acrylic rod segments (1/2" round) whenever possible (... virtual invisibility ...), it flexs unacceptably after 10" - 12" (less, depending upon the weight). It's also potentially problematic to anchor to a support structure either within, or outside, the tank.

On the other hand, if you're talking about connecting an overhang piece to another existing and stable piece, AND if the weight of the new overhang piece doesn't destabilize (... unacceptably shift the center of gravity ...) of the "base" piece, then I use 1/2" acrylic rod segments as "connectors." Meaning ... I drill holes in both pieces, and "Holdfast" epoxy the acrylic rod segments into the holes forming a "connection." After the epoxy cures, it's very strong.

HTH.