System Design

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fishkisser

Member
I am in the process of researching many issues related to reef keeping with my system design in mind. I wanted to put my thoughts out here that contrary opinions may be aired. Thus exposing me to ideas that have not occurred to me.
Assumption: it is very beneficial to expose as much of the sandbed as possible to overall water flow for the main purpose of nutrient exchanges and to minimize nutrient buildup.
I plan to build a (rock) frame network of PVC that is also connencted in part(not full flow) to the return circut. The frame will contain drilled holes of a yet to be determined size and be sturctured in such a way as to support rock at many different angles and with overhangs as well. All rock will be at least 1.5-2 inches above sandbed. Comments please!? :columbo:
 
ReefLady

ReefLady

Well-Known Member
Staff member
Just thinking out loud. Are you going to be able to devise the PVC structure so that it is not visible? Will it be mostly underneath the sand? Why the holes drilled in the pvc - I'd be afraid they get clogged over time (detritues, coralline, etc).
Are you planning on having water flowing through this pvc? One concern would be if you ever needed to repair or replace a piece of the pvc structure, it would be difficult to get at.

Sorry if I'm not fully understanding. My husband would definitely verify that I have trouble conceptualizing anything that has to do with structure/design. ;-)
 
reef dummy

reef dummy

Member
You could just place the rock directly on tank bottom then add sand thus exposing all sand to water current and eliminating sand under rocks that collects detritus. This is a much simpler solution I believe.
 
F

fishkisser

Member
You are not fully uunderstanding because I was not articulate enough and thought my post already quite long!
Pains would be taken to make the frame as much out of sight as possible with perhaps 45 degree down angles. In time the growth and addition of corals would cover cracks not initially covered by rock. The functional part of the frame would be outside of the sandbed although it will be anchored on the tank floor. And yes, my thinking at present is that a 1/2-1' bulkhead at or near bottom level would feed water to the frame/PVC system. There would be no circulation from the frame in the sandbed, only above it in the rock formation. With a lack of light it is my hope that little or no coraline algae will block the holes. The whole idea is to maximize circulation above the sand bed by not blocking its surface with rocks AND to circulate water around the rocks back sides as much as possible.
 
ReefLady

ReefLady

Well-Known Member
Staff member
Okay, got it (I hope). My opinion only -- holes of any size are going to eventually clog. Either with detritus, coralline, other algae growth, sponge growth, etc. - I'd pretty much guarantee that they'll clog.
Personally, here are the options I would think of...

Place the rock directly on the floor of the tank (as reef dummy said), or,
Place on a pvc/other structure, but nix the idea of trying to flow water through it. I'm not saying it can't be done, but I think it might be more trouble than it's worth. Get a good sand sifter (star or other sand stirring critters) to keep the sand "moving". Good, multi-directional water movement will help as well.

Again, keeping in mind that I am mechanically challenged, where would the water come from to feed the bulkhead into the frame/pvc system? And if the power went out, could that bulkhead potentially drain the water of the DT tank down to that level?

I think the overall concept of flow & movement around the base of the rock is a good one, so don't take my word for it that it won't work. :)
 
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fishkisser

Member
the bulkhead would be at bottom level and would be feed (in part)by the return pump. The outside PVC would be a upside down "U" that would be above water level and the top of the U would have a bleeder valve to allow any air that might collect there to escape.
Rocks directly on the bottom would defeat one of my main objectives which is to maximize sandbed surface area.
Thank you soooooo much!! See! I never considered the clogging of the holes in the long run. Perhaps the only thing that will survive from this idea is the frame itself. And raising rock above the sands surface in and of itself is hardly new although I obviously believe quite effective.
 
ReefLady

ReefLady

Well-Known Member
Staff member
Hey, I didn't mean to kill your plan, sorry about that. I've pulled apart several tanks, and I know that eventually, even the live rock gets so overgrown with "stuff" that it's pretty much welded together. I do think that the frame idea would work.
One other thought (though I'm sure you've probably though of this) - is if you want to maximize sb surface, attach a refugium with a sb. Although I do agree that somehow suspending the rock above the substrate has value.
 
F

fishkisser

Member
Thank You Lynn!
It just occurred to me in between posts that if I made the holes very very large I could still control the flow through a external valve and extend the life of the device from clogging.
 
F

fishkisser

Member
In your opinion how long to clog a 1" PVC with a 1/4" hole? Just a ball park based upon your experience and NO, i will not hold you to it!!! LOL LOL
 
ReefLady

ReefLady

Well-Known Member
Staff member
I guess it depends on what you have in the tank (corals, shrooms, polyps, etc), how "live" your live rock is (sponge growth, etc), but I'd guess 6-8 mos. Maybe a little longer.
 
reef dummy

reef dummy

Member
I agree with ReefLady. I think you are overthinking this system design. You don't need to do what I think you want to do. A simple dsb of 5-6 inches will suffice in helping with your tank parameters.
 
T

Tim Patterson

Member
My tank has a bare bottom (accept what grows on it) but I have 6 inches of sand in the refug. Tank is doing great and I have no Nitrates. I think that sand in the tank causes more harm then good and is a pan to maintain.
Tim
 
ReefLady

ReefLady

Well-Known Member
Staff member
It's all good to think everything through before setting it up. I wish I had taken better pictures when our tank was set up, but here are just a few things that grew out of nowhere...

This orange clathrina sponge would crop up here and there in an attempt to suffocate my zo's and some corals.

clath.jpg


This white (leucosolenia) sponge loved dark areas, and was rampant in the sump (even with pretty turbulent water flow):

leuc.jpg


I like your idea, and am not trying to discourage you, I just think (IMO) that running water through the PVC might be very difficult to maintain over time.

I've had many many tanks. My next tank will have a very shallow sandbed (for aesthetics only). I'll probably place the rock directly on the floor of the tank. I'm not really concerned about sand surface area, because (1) IMO, the LR provides enough biological filtration/denitrification/microfaunal diversity, and (2) I'll more than likely have an attached refugium with a SB.
 
Basile

Basile

Well-Known Member
Hey, hi just was introduced to your thread by Lynn. We seem to think alike. I'm building a structure that will support my aquasculpture 4 inch above the tank floor. The ideal here is to have 3 inch of sand and 1 inch of free space under the rocks to allow the water flow. I also have one of the structure possibly hooked to my return pump, from a top. You can check this out here
http://www.reefsanctuary.com/forums/reef-chronicles/39606-ok-65-g-slowly-but-best-i-can-make.html, the thread is also in my signature lol, clored pink no less lol. Ok lets connect and exchange ideal on this one, we seem to have the same goals.
 
Wakeskater02

Wakeskater02

Member
Here is an idea that my fish store did on a 190 that we had. We used fiberglass rod, to hold our rock formations in place. It is great because you can set the rock exactly how you want it, it looks really natural and the fiberglass rods are hidden.

To do this just get a large drill bit maybe 12" long and drill each piece of rock. Set the rod in the tank and then stack the rock on the rod. It works very well. If you have a long piece of rock you can drill through it and then stick a fiberglass rod through the rock and then angle it on the corners of the tank so that the rock is basically hanging from the corner of the tank, that also looks really cool!
 
PEMfish

PEMfish

Well-Known Member
The large holes would let all the water flow out of the first few.
Attaching the PVC to the tank floor could break the tank if the rock shifts and puts stress on the glass.
 
F

fishkisser

Member
Basile:
We do have a common goal,to maximize the active surface area of our sand beds.
I plan mine to be much deeper, 4-6". From what I can tell DSB acting as nitrate sinks runs parallel to inadequate water movement and flow on the DSB's surface area(saving other contributions like over feeding or dead animals ect.). It is my hope to turn the water (estimated actual water for 300 tank, 2-100 fuges and 50 gal sump to be aprox 450-500)20-25 times per hour.
I will use live rock and my frame, made of PVC will hopefully double as a source for water movement although there is a concern I hadn't thought about, namely the clogging of the drilled holes.
Drain will be coast to coast with 3-2 1/2 " bulkheads.
 
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