From: steve@celia.UUCP (Steve Tyree)
Newsgroups: rec.aquaria,alt.aquaria
Subject: Re: [M][R] [LONG] Improving Captive Reef Base Rock
Keywords: reef marine coralline live rock
Date: 4 Sep 92 18:54:35 GMT
Reply-To: celia!steve@usc.edu (Steve Tyree)
Distribution: usa
Organization: Rhythm & Hues, Inc., Hollywood


 Heres a summary of mail I received dealing with elevating a portion of
my reef and adding extra circulation. The reason I am doing this is to
try to eliminate all detritus and eventually 99 percent of all hair algae
growths. My tank has unmeasurable phosphates and nitrates with Lamotte
low range test kits but hair algae still grows. Its possible that the low
quality live rock base rock I am using is also promoting hair algae growth. 
--------------------------------------------------------------------------
editor writes -
 The first controversy involves the subject of raising or elevating the
base reef off the tank bottom. This poster thinks that elevation is not
the best solution. 
---
From: Steve Rader <usc!ssec.wisc.edu!rader>
You seem to imply there is some correlation between detritus
collecting at your reef base and hair algae growths nearby...  I
think you'll agree that there is only a correlation between amounts
of detritus and hair algae growth.  The reasoning: algae take up
_soluable_ nutrients... detritus, _regardless_of_it's_location_
creates a nutrient bank that maintains a base-line of available
(soluable) nutrients.   Adding a live-rock shelf will only
change the *location* of the detritus; and thus will not improve
your overall trophic level.  My point is this:  The shelf will
not help in and of its self.

On the other hand, one might argue that the shelf will allow
for more efficent removal of waste which will limit microalgae
growth.  This may or may not be true--I think the verdict is still
out on that 'en.  Clearly, if adding a shelf will increase your
frequency of sucking detritus then the self will improve your
water quality.

But, I strongly doubt that a reef ontop of a self will allow you
to get at more detritus than will a reef with an empty bottom
(no substrate.)   This is just my gut reaction from spending
eight years limiting detritus and have a empty-bottom reef for
almost three years.   I'd bet good money that if you did not
spent the time building and installing the shelf, but rather
spent that time puffing with a baster, syphoning detritus and
cleaning prefilters that your NO3 levels would drop more.

To me, the bottom line goes like this: water quality is a
function of how much and at what frequency detritus is removed
from our closed systems.  IMHO, a empty-bottom tank allows
very good access to syphoning detritus; in relative terms 
perhaps a much a 95% the access of a shelf.  (I maintain 
less than .2 ppm NO3 with my bear-bottom reef.  As opposed to
the < 10ppm standard of the '80s)  The payoff doesn't seem
justified, especially if you keep featherdusters, sea cucumbers,
or any bottom dwelling inverts.
---
editor writes -
 He makes a good case for not elevating, however with a large tank like
mine (2' deep, 2' high and 6' long) cleaning detritus from every possible
live rock contact point is very tedious. My goal is to create less areas
where detritus can collect. 
------------------------------------------------------------------------
editor writes -
 The next set of posts describes various methods of egg crate elevation
that have been utilized by fellow reefers.
---
From: usc!nicsn1.monsanto.com!kncarp (Kevin N. Carpenter)
The basic design we came up with is a large PVC pipe (1") that runs the
length of the back of the tank.  I drilled 3/16th holes every 5 inches or
so.  If I did it again, I would put than a little closer, say 2.5-3 inches.
Do the math and compute the right size holes based on the number you want
and the size main pipe you are using. (I figured the cross-flow area of
the feed pipe (.25PI for a 1" pipe), divided by desired number of holes,
and back calculated drilled hole size.  I felt errors should lean towards
smaller holes to keep the pressure up the entire length of the pipe.)
Both Keith and I wanted a small amount of substrate in the front of our
tanks for macro-algea growth and those few critters that seem to enjoy have
a "sand box".  I used a PVC corner tee to pipe some water from my main
feed pipe along a side PVC pipe and then split that into two parallel
1/2" pipes that run the length of the front of my tank.  These front pipes
are drilled and provide a RUGF like environment when combined with my
eggcrate fronts.  The eggcrate was vertically cut at a 45 degree angle
across the front, to which a clear strip of acrylic was siliconed.  I also
siliconed a eggcrate support strut from the base of the acrylic up to the
main eggcrate plate.  This strut was designed to provide the front support
for the eggcrate, the 1" PVC pipe provided the back support.  I'll take a
stab at an ASCII graphics in abit... (Oh, this is in use on my 135g tank,
so the dimensions/support issues should be close).  

I've found the eggcrate can support the weigth of my live rock without any
problem.  In spots my rock is about 8" high.  Besides more holes in the back
pipe, I would change two things if I did it again:  1) I used three panels
(two feet wide each).  In a new setup, I'd use 6, each a foot wide.  Once in
awhile, something (like an bubble anemone) will work its way below the
eggcrate and will need to be removed.  Its a lot easier to move 1/6th of 
the live rock than 1/3rd...  2) Rather than sandwich my substate between the
tank front and the eggcrate front (over the RUGF pipes), I'd build a trough
from acrylic (back and bottom with PVC pipes on resting on the bottom) and
just lay the eggcrate against it.  That way you do not end up removing one
support wall when you remove the eggcrate.  I do suggest the angled cut
on the eggcrate and matching angle of the substrate retaining wall.  This
keeps the eggcrate firmly against the back wall and provides good support
as well.  The strut ended up being redundant, one of mine has fallen off
with no deflection in the eggcrate showing.  Likewise, one of the substrate
back walls (front of original eggcrate piece) has decided that substrate
bonding was better than silicon and stayed put when I pulled out that piece.

OK - I'm out of time for now, let me do a quick ASCII drawing.

|							     |
|							     |
|							     |
|							     |
|							     |
|    \							     |
|     \######################################################|
|_o_o__\____________________________________________________O|


Where "o" are 1/2 PVC, "O" is 1" PVC, "#" is eggcrate.

Oh, the design objective here is to blow all the detritus from the back
of the tank to the front for easy cleaning.  In my tank it works like a
charm.  The only thing I have a small "V"s of sand across the bottom of
my tank between the holes in the back pipe (thus my desire to put the
holes closer together).  Also - I drive this whole mess with a Quiet
One at an estimated 700g/hour.  Don't under power it!
---
From: usc!IRENE.MIT.EDU!MENUDO (Roberto Estrada)
     I have set up a couple tanks with variations on the design
in Feb.1992's issue of FAMA(p. 176, Pier to Peer).  It works great and I put
a similar design in my already established 40gal reef tank.  My design takes
the output from an 802 powerhead (in the left back corner) and the Magnum 330
(on the right hand corner) to push water flow forward.  I then take cleaner 
magnets and push the detritus forward for siphoning.  I've seen increased 
size in the corals from the improved water quality and turbid water flow.
---
editor writes -
 The article referred to in the above post describes a reef elevation
system using egg crate and two power heads for circulation.
---
From: usc!uunet.UU.NET!wpsun4.uucp!jimpe (Jim Perry)
I designed my reef to have all the live rock on a egg-crate sheet.  The egg-crate does not cover the whole bottom.  There is about a 4-5" margin along the front
and sides that does not have the egg-crate.  From the top it looks like this:

__________________________
| |xxxxxxxxxxxxxxxxxxxxx| |
| |xxxxxxxxxxxxxxxxxxxxx| |
| \xxxxxxxxxxxxxxxxxxxxx/ |
|  \xxxxxxxxxxxxxxxxxxx/  |
|   -------------------   |
|_________________________|


The x part is the egg-crate.  In the middle, at the back, is where my water
return is from the filtration system. It blows water toward the sides. 
I also have a large powerhead in the middle at the back which blows water
toward the front.  The border around the egg-crate is acrylic, about 2" high.
The advantage of this system is that all the detritus and dirt collects in the
margin around the edge, which has only a single layer of odd, small rocks to
basically hide the acrylic border.  These rocks move easily, and it is easy to
siphon 100% of the gunk out by just siphoning around the edge. The part that
is under the egg-crate stays free of gunk.

Now, I would beware of using just pvc with holes drilled in it to provide the
flow under the egg-crate.  A local dealer did that with his 180 reef and the
flow was not enough - stuff builds up still, and is virtually impossible to 
clean.  
My setup is ideal in that if I open the water return valve all the way and pump
800 gph though the return, I can blow even small pebbles out from under there.
Of course, I usually keep the flow in a normal ~300 gph range, but I need the
aquaclear 800 powerhead as well to do the job.

My point is, make sure you have enough flow, or larger stuff will stay under 
there, and collect smaller stuff, which will collect smaller stuff, etc. until
you have gunk city.

I have never had measureable nitrates with my reef.  I use LaMotte kits.  I 
use only foam fractionation and NO wet/dry nitrate factory.  Once a month
(or so) I siphon the stuff from around the edge.  I believe my system is as
low maintenance as it could be!
---
From: usc!inel.gov!crayfe2 (John L Metzner)
I have the egg crate raised by egg crate blocks glued to the 
bottom.  The blocks are 3x2 cubes of egg crate glued with the 
pvc pipe fitting cement.  They don't block circulation like 
plexi might.  
---
From: Carl <usc!WVNVAXA.WVNET.EDU!SH240031>
	I got nervous about the weight on the crateand the next thing I knew
I had a support piece every three inches.  This was undoubtably just 
paranoia and looking back on it, considering the weight reduction in water,
and the fact I was only going 2 full cubes of crate high, I probably should
have just went with it. 

	To get PVC under the crate you my have to go  3 or 4 cubes high,
if your crate is the same size I had and depending on what size PVC you use.
---
From: usc!inel.gov!crayfe2 (John L Metzner)
	The egg crate doesn't reach all the way to the walls of the tank.
There is a half inch gap down each side of the right angle.  My spill
over is across the right angle corner in the back and is about 12 inches
wide.  There is also a half inch gap between the egg crate and the spill
over wall.  Across the front there is about a one inch gap between egg
crate and glass.  The two 45 degree corners are the only place where I 
have a significant gap, a triangle about 2 1/2" on a side.  All these 
areas I have filled with some crushed coral to prevent shifting and hide
the front edge of the egg crate.  So far I haven't had much of a nitrate
problem, ~10 ppm.
	As far as another material for the screening, I haven't looked for
any.  The first time I had the tank up and running (old filtration) I 
didn't have a bubble problem.  I now have an Ocean Clear Power Trickle
filter without a Chemicle Canister between the trickle and the return 
to the tank.  I believe this is why I have such a bubble problem.  The 
Chemicle and 25 sq. ft. paper filter should arrive today.  I'll get
those set up and then see if I need to do anything about the screening.
I am concerned that if I go to a larger mesh of some kind those little 
boneless critters will find a way of squeeeeeezing through.
------------------------------------------------------------------------
editor writes - 
 The following posts describe problems encountered with egg crate eleva-
tion.
---
From: usc!cco.caltech.edu!laurence (Dustin Lee Laurence)
I made one awhile back, but finally got rid of it.  It worked wonderfully
for the first few weeks, but I started to get hair algae growth under the
eggcrate (where no herbivores could reach it --it was only about 1/2 inch
off the bottom) in the spots where the MH light hit the bottom directly.
I get no growth on exposed bottom without the eggcrate, so apparently a modest
amount of predation keeps the glass bare.

I very much liked the idea of having the rocks elevated, though, and I've
been considering trying again.  It might work if I can elevate the rocks
individually without covering the whole bottom with plastic mesh.  Failing
that, I might try to re-construct the reef (when I get the new tank) with
some large flat pieces so that much of the bottom is bare.
---
From: <usc!uunet.UU.NET!wpsun4.uucp!xunixcon!smtpx!jimpe>  (Jim Perry)
 The egg-crate rests on top of these, and just fits
inside the acrylic border. Someone posted recently about an anemone
slipping down under the egg-crate and dying - I don't have this problem
because the acrylic border just fits around the egg-crate.  Nothing
larger than the egg-crate grid holes can fit under there.
---
From: usc!inel.gov!crayfe2 (John L Metzner)
Something else I have on my egg crate which I like, is window screen
fiberglass mesh.  I didn't think much about it until I saw some
postings on the net about fish and inverts getting under the egg
crate and dying/decomposing.  It is stretched over the egg crate and
attached with hot glue around the edges.  The disadvantage is if
there are small bubbles in the return water they can become trapped
under the screen and build up.  You either have to burp the screen
by tapping on it with a feeding stick or you occasionally get a 
'depth charge' go off.....not pleasant and fix is in the works.
---
From: Carl<usc!WVNVAXA.WVNET.EDU!SH240031>
	I ended up using small peices of rock on the bottom to make a
platform for the larger rocks. I started out with eggcrate, but didn't
like the way it looked.  By placing the small rocks between the holes in the
pipe, I seem to have maintained a good under flow.  Still, some of the holes
are obstructed and undoubtibly a better solution exists.
------------------------------------------------------------------------
editor writes -
 The next set of posts describes methods which add reef circulation with-
out using elevation.
---
From: Carl <usc!WVNVAXA.WVNET.EDU!SH240031>
I recently constructed a flowthrough system using PVC and a power head to
insure flow behind my reef.  My setup consists of a 55gal tank and about
120lbs of live rock.  I was worried about water flow behind and underneith
the reef, so i ventured to various shops and found one with a 135gal tank
that had what I feel is a good method of circulation.
	A PVC pipe, in my case 3/4" in the shop 1", extends the length
of the tank behind the reef.  It tees in the middle and extends toward the
surface.  In the pipe are drilled 5/32" holes every 2" in my case and 3/16"
every 2" at the shop.  Both sides of the pipe along the bottom are capped.
The holes point a few degrees off the parallel of the bottom of the tank
so to direct the water at a slight down angle.  Also, every 6" one hole is
drilled perpendicular to the bottom to provide flow upward along the back 
of the reef. 
	Due to the limited pressure of my sump pump I have an Aquaclear 402
providing my flow, whreas the shop has theirs plumbed in to the return from
the sump.  I get great circulation from this arangement as is evident by the
detritus that buils up along the front of the tank.  Here it is easily removed
with a siphon.
---
From: <usc!uunet.UU.NET!wpsun4.uucp!xunixcon!smtpx!jimpe>  (Jim Perry)
My water return goes into a tee, which then has the clear vinyl tubing
going back down under the egg-crate. The tee stuck up too high to fit
under the egg-crate.  The egg-crate rests upon pieces of cut pvc pipe.  I
used 1/2" I think, and cut the pieces into 1/2 inch long pieces.  I laid
the pieces down on their sides, figuring that if they were upright, they
would collect major gunk inside where the water flow didn't reach.  I
angled the pieces in a way so that the pipe pieces were in-line with the
water flow from the filter return or powerhead.  This keeps water flow
through them and prevents "stale" areas where detritus can build up.  I
had to silicone them in place, since they would tend to move around from
the water flow.  The egg-crate rests on top of these, and just fits
inside the acrylic border. 
---------------------------------------------------------------------------
editor writes -
 The following posts deal with using pvc pipe for elevation and methods for
drilling holes in the pvc are described.
---
From: usc!inel.gov!crayfe2 (John L Metzner)
> Whats the best grid pattern and spacing for pvc ?
	I don't know about best but I can tell you what I'm doing that
	seems to work.  In my 45 gal. corner tank I upgraded the original
	single spray bar under the RUGF to 3, 1" pvc equally spaced.  That
	works out to 6" on center between the 3 tubes.  
> How many holes and on what sides of the pvc should they be ?
	In the process of the upgrade of the pvc, I changed the pattern and
	angle of the holes and their spacing.  When I tore the tank down
	for the repairs, there was a fair bit junk under the egg crate.
	From the pattern I could tell I needed to do something about the 
	single spray bar return pvc.  When I drilled the holes for the new
	tubes, I drilled them about 15 degrees below the horizontal so
	looking down the end of the tubes the holes are at about 8 and 4
	o'clock.  I also staggered the holes on opposite sides. The holes 
	are 1/8" diameter.  Along with these changes, I installed a Little
	Giant MDQ2-SC pump to power the filtration.  With the holes canted
	down and having holes along the outside edge of the pvc, I don't 
	get an appreciable amount of junk building up under the egg crate.
	The tank has been up and stocked for over 6 months with the new pvc
	and there isn't any mulm to speak of under the crate (I have
	several viewing holes (~2" diameter) drilled in the tank stand 
	underneath the tank to check up on what is going on under the 
	crate.).
---
From: Carl <usc!WVNVAXA.WVNET.EDU!SH240031>
	When I was planning out what size holes to use, I consulted a
Physicist on campus.  He explained that fluid dynamics is a very complex
subject. So he worked up a model for me using the flow rate of the pump
the diameter of the pipe, and the distance to be traveled to determine
what size and how many holes would be needed.  After we had it laid out
we tested the apperatus by attaching the powerheadand submersising it
inverted in a bucket of water.  The flow was fairly uniform, but no
quite perfect along the entire length.
---
From: usc!msc2.msc.cornell.edu!lawrence (Lawrence H. Smith)
Steve: another possibility for partial elevation, without all those little
bits of acrylic to keep track of: 1-1/2" pipe along the back, and out at
90 degrees from the back as the back "row" and all the "columns" of the
 matrix. all the other "rows" of 1/2" or 3/4" pipe, either centerlined on 
fittings (that's a lot of fittings) or biased towards the top if you are
drilling the larger pipe to take the smaller pipe (save a lot on fittings)
(need a good drill press and jig, I think). Leave the front "row" off.
this way, you have a number of bays, not the whole under-reef; but the bays
are well supported as an integral part of their structure, and cannot
shift off their supports as you place rocks on them, which might be a 
problem with the whole grid on blocks.
---------------------------------------------------------------------------
Editor writes -
 So that was the summary of mail received from my original post. Thanks a
lot for the information netters. Hope this summary can be of benifit to
others. Please go ahead and comment on any ideas contained within. I will
post a basic design for the pvc matrix manifold system which I am think-
ing about constructing this weekend.

 Steve Tyree - Reef Breeder
From: frankb@hpsad.sad.hp.com (Frank Ball)
Date: Mon, 31 Aug 1992 03:58:56 GMT
Subject: Re: Goldfish sick: Help
Organization: HP Signal Analysis Division - Rohnert Park, CA