Internal overflow box for 360g reef

[nsamouroux]

My 360 gallon aquarium is undrilled (for now!) and has a full top with two very large openings in the top and a slit in the back. These openings are insufficient to construct a permanent internal coast-to-coast overflow, and I don't have the space for an external calfo / coast-to-coast, so some brainstorming was required. Someone on another reef message board mentioned the overflow boxes that Glass holes.com builds, which are perfect for my intended design since they are made to be used to a non-reef ready setup.

I ran down to TAP Plastics and purchased a 2' x 4' sheet of 3/16" cell-cast acrylic and a couple of cut-off pieces for the side panels and internal braces. I chose to stick with clear acrylic rather than opaque or smoke-tinted because I want to be able to see what is going on. The tank will be up against a wall with a full canopy, so I want to be able to see the inner workings through the front of the tank to make sure nothing clogs and no fish are trying to cuddle with the bulkheads. Also, the clear acrylic won't block light from the halides, so I don't have to worry as much about dark spots. I anticipate having to scrub out the overflow box every few weeks, but the amount of flow should keep it fairly clean and free of algae buildup (famous last words!). The shop cut it for me into the sizes I needed and set me up with some weld-on 16 to bond it all together. The overflow will be 4' long x 8" tall x 6" wide, which will require some additional bracing on the horizontal since I'm using thinner sheets on a long run (would have been more than double the cost to use 1/2" acrylic and would still need bracing). I intend to set this up as three 2" sch80 bulkheads with external durso risers (the design used by Beananimal for those of you who visit R.C.'s forums) and will be running approximately 2,500 gph through it.

Enough blabbering, on to the pictures! Below is the sketchup design I came up with for the overflow box itself. The internal braces are placed about 1.5' apart, 2" above the bottom panel, and 1" from the top to allow water to flow equally to all three chambers. I may have to put in an additional two braces between the existing ones and the end panels to further reinforce this.

And the overflow box in it's final resting place inside the tank. Everything is drawn to scale for accuracy:

Can anyone see any problems with this setup before I start inhaling copious amounts of weld-on and cutting holes in my aquarium? Critiques are very welcome, since they will most likely save me from horrible mistakes that I would otherwise have made Thanks in advance!

 

[tat2z_21]

Do you plan on using any kind of pipes for silencing the water as it goes down. It seems to me that with three 3 1/2 holes it will be a lot of water going at once. level of noise from the gurgling might be a little excessive. Also with 3 1/2 in holes there will be alot of transfer of water to the sump. Make sure you have the right sized return pump to handle that kind of water movement. Other then that it looks as if it will work just fine. Also remember that the boxes will determine your water height and looks to me that you have them flush with the top. I know it is just a drawing and you will make it work just a heads up.

 

[nsamouroux]

The overflow will sit close to the top of the tank (perhaps 1" below it). I haven't decided if I want to cut teeth into the overflow or just leave it as-is and protect it with gutter-guard or egg-crate... The 3 1/2" holes are needed for 2" sch80 bulkheads. I'll have a 90* fitting on each of the bulkheads inside the overflow box, and a T-fitting off the back with a riser tube extending up to the top of the tank. This will form a standard durso drain pipe on each of the bulkheads, and should be almost completely silent. One of the three 2" drains will be a normal durso with air hose, the second drain will be act as a full siphon (no external air allowed inside), while the third will have the 90* fitting facing upwards and will be used as an emergency drain incase one or both of the other drains somehow become blocked. A 2" drain like this can flow 1300gph according to wetwebmedia's tests (double that for a full siphon, so any one pipe could handle the full flow under a full siphon condition), and I'm only running 2500ish gph through this. Technically the size of the overflow doesn't matter as long as it is capable of handling whatever water the return pump can flow. I could hook up a 500gph pump as the return and the overflow would only have 500 gph running through it. This overflow is a bit oversized for my 2500gph goal, but if I change pumps or sump design I can probably accomodate up to 3500 gph safely (perhaps adding a fourth drain for safety's sake). I settled upon the 2500gph number because it gives 7x turnover through my sump for filtration, and matches the gph of my skimmer pump.

EDIT: Also, my sump will reside in an unfinished basement, with the pipes running down through the floor beneath the tank or perhaps through an old chimney next to the tank. As long as the noise happens down there, I'm happy with it

 

[plack]

The 6" Front to back will kill allot of lighting space.

The clear acrylic will become a great fuel sorce for algae go with solid black.

I ran over 1700 GPH Actual return Through one 1.5" Drain fairly quiet hough not silent for years.Before slowing it down to about 750 GPH !!

Sompthing to ponder-- Say your skimmer is close to or directly fed from the overflow and imagine that the skimmer pump is 720 gph and that your return rate is the same. This way everthing drained off the top goes thru the skimmer. as opposed to say a fast flow rate with the skimmer getting only a portion of the drained water skimmed. So why run it faster !!!

Back to the overflow box itself.

My 180 AGA with internal Acrylic overflow was run coast to coast and 4" front to back and it was MAJOR Overkill as far as the 4" front to back goes.

One one hand it gives it more strength to glue to the glass But it Takes away from the Tank lighted space allot.

The bulb is a point and it goes out in sompthing like a pyramid shape to the bottom of your tank and this will stop some especially at the top back !!! and become an algae source being so close to the light

- you'll want to cover it with Blackeggcrate and or some kind of material to stop the light as I did.

I also believe in creatng a vortex either using a closed loop and plumbing it with 2 pumps one for each end and having the water run lengthwise 3" under the surface alternating.
A fast return messes with a vortex.

I am using a 1000GPH pump per side alternating this way and it crates more flow than a 4700GPH closed loop with zero head did because it was not running 3" below the top and it was not running the water in the long direction of the tank. I actually can have too much flow and have to slow it down so the sand bed isn't all tossed up on the bottom !!

Just some thought's



Paul
Washingtonians Please join the members of the P.S.A.S. and learn more in person !

 

[plack]

Are you coming to the frag swap the Psas is having on Sept 19th ?

Also the top holes if cut with LARGE radius's in the corner's instead of the almolst sharp looking ones will give it more strength why risk a future crack from the stress points.

Not exactly sure what the second smaller set of rectangles is for? I think they will loose strength for taller tanks as well.

I am curious what are the round holes in the top back sides for?
I assume you will have a sump and so you should not really need these as I understand thing's ?



Paul

 

[nsamouroux]

The dimensions of the tank is 8' long x 3' wide x 25" tall, and was purchased from Tenecor, it is their commercially-made 360 gallon. The tops, the two slits in the back, and the holes at the corners are how all of their tanks are made unless something else is specified. I figured I could make it work and save $1000 or so . I was going to use the holes at the corners for my return lines from the basement. The slit in the back of the tank is wide enough to get a scrubber brush inside the overflow for cleaning (but not big enough to fit plumbing into, so couldn't make a glued-in overflow), or if the algae gets particularly bad I can just drain the tank down to the level of the bulkheads (about a 15% drain) when doing a water change, unscrew the bulkheads, remove the box, and clean it. I'm using the clear acrylic because I have to be able to see into the box from the front or side of the tank, as it's going to be up against a wall and I'd need a ladder to climb on top of it to check things from above (not to mention moving or fully opening an 8' x 3' full canopy!). I will have a piece of black acrylic for a cover, but because of the width of the tank and the angle of the lighting out of the lumenarc reflectors the overflow box won't get any direct light at all. I had a similar setup with a smaller top corner overflow box on a smaller tank (my current 100 gallon reef) and it doesn't grow any real algae. The 6" width (front to back) of this box shouldn't block too much light, especially since it's clear and the center of the halide bulb will be almost 1.5' away from it, so the downward angle from the reflector won't fully reach there anyways. If I do end up with turf-scrubber algae growth in the overflow, I can just remove it and paint it black with some Krylon fusion and leave the bottom and end panels clear . This would at least let me look through the sides to make sure everything inside is working as intended.

My skimmer is a larger downdraft style, so there's no way to feed it from the tank overflow. If I ever switch to a venturi / needlewheel skimmer with recirculating pump(s) I'll certainly set it up the way you suggested with the overflows running the skimmer. The only reason I am putting so much water through the sump (which isn't really that much considering the total system volume, only 5-7x turnover) is because that number matches the gph on the skimmer. I'll probably dial it back a bit, but 2000-2500 gph is my starting point.

You're correct, I will have a sump (probably converting my current 100g acrylic tank into one, along with a 150ish gallon rubbermaid stock tank) that will reside in my basement, with all plumbing running from the tank down through the floor. In trying to save some $$ on the upgrade, I'm steering away from a large closed loop since I'd need at least a hammerhead pump, (or perhaps two!) to achieve my 40x turnover goal. Since it'll be a mixed reef, some areas will have higher flow for SPS, while some are somewhat lower flow for softies. Instead of the closed loop I'm planning on using four Koralia Magnum 8 powerheads and two of the Koralia 4 pumps that I already have will be lower in the tank angled upwards to create more of a rolling pattern as you mentioned. Eventually once I get a controller for the Magnums I'll set it up in an alternating (side-to-side) manner as you mentioned. All of the wiring, and probably the Koralias themselves will be hidden by the full canopy, so I still achieve the "hidden equipment" appearance of a closed loop

 

[plack]

Wow 3 feet wide that souds nice.

If you have your heart set on korrilas then try just 2 having one placed 3-4" below the top on the center of the right and left on timers every 10 minutes throw in a little flake and you should see a strong vortex.

The key to it's strength is the speed along the top. that will force all the water to follow it ! I have only 1000 GPH shoving 180 around ALLOT. it is being Forced through (2) 3/8"X1" slots per side and it moves upward just enoughp so the halides don't get drenched but creates a strong undertow.

The broader the flow the slower the speed thus the less power for a vortex.

Normally everyone things broad flow. But this is not directly aimed at any corals it's above them--

Just a few inches away or below and it is a strong moving broad flow.

Some people aquascape so that they don't have coarls near the ends and also near the top so this would not cause a problem.

The undertow can get so strong that a blasto welski on the sand seems to get too much flow and so I make the 3/8" X 1" slots a tad wider (dremmeled out of a pvc cap).

You could even do this with your return using say 5 slotted out pvc caps for free less cost of some pvc pipe to try it out !!!.

If you got a motorized ball valve ( yes spendy) it could alternate the sides for you. from what I understand moterized ball valves are dependable.

This would cost less than 4 korillas And you could try it first on 1 side of your tank for free . You could hook it up withboth sides and just manually change it to see 100% what it would look like But thats a pain.

Just some thoughts

I may try this some day, this or Vortex M40's would seem optimal. But they don't create as strong a vortex as the method I suggested as I have seen 1 M40 going full out and it's not near as powerfull on the bottom return at least in a 4 foot tank .

There used to be a company around here that sold acrylic tanks and had issues with the top cracking. Now they used 4 pcs for the top and all the edges were sharp not the same as what you have but after seeing several people in person with the failed design I just wanted to let you know about the potential stress areas.

 

[nsamouroux]

The design of the top panel (and with most of the tank only being 5/8" acrylic), is what made me focus on an internal overflow. I didn't trust the rigidity of the tank if I added an external overflow and had to cut a weir into it for surface skimming, especially with the back of the top panel already having the two slits cut into it. I decided not to do a closed loop in part because of the same issues, I don't want to put too many holes in this tank and risk a failure. I don't have enough buckets to keep that much water off my wood floors I prefer a "no equipment" look in the display, but am warming up to the koralia pumps. I have two k4s in my 100-gallon and they work great! I can't wait to see what two of the Magnum 8 pumps will do in the 360 gallon... They're the highest flow pumps (3200gph) with the lowest power draw (18w) and I can pick them up for $120-$140 each. Hydor is now making them controllable, so that's an added benefit. I can always move around powerheads as needed when corals grow in, but re-doing a closed loop system (which I would have had hidden in rockwork) is MUCH more difficult and I would probably have ended up with some powerheads anyways for the inevitable dead spots. I don't think I can put in a wave box / surge tank and not risk a big mess on my floor, so the alternating koralias look like my best option. I'll start off with two of the Magnum 8 pumps (one on each side panel of the tank) and my two k4 pumps on the rear panel on either side of and just below the overflow box, which should keep them somewhat out of sight. Eventually I'll put in two more Magnum 8 pumps in the rear side panels (top corners) and get a controller so that I can alternate the sides as you mentioned (one side fires for 10 minutes, then turns off / reduces flow and the other side kicks in full blast). The rear panel pumps on the back wall will run 24/7 and provide a breakup of any laminar flow (not too much from these with their wide output "cone"), as well as keeping current on the front panel.

 

[nsamouroux]

It lives! Built the thing over the course of 2 hours this morning and just finished the wet test (allowed the weld-on 16 to dry / cure for 6 hours). It's not pretty, but it holds water just fine with no visible deflection. I also took it out back into my son's 800ish gallon pool and tried to submerge it to mimic the pressures on it when the tank is being filled. I was only able to submerge it 1/2 way, but noticed no visible warping / deflection in this test either. It gets my redneck engineering stamp of approval! I re-checked Savko and a few other sites and realized that I don't need 3 1/2" holes for the 2" schedule 80 bulkheads, I need 3 1/4". Close call!

It'll be at least a few weeks before I'm ready to start working on setting up the tank itself to replace my 100-gallon reef (have to do plumbing and set up the basement "fish room"), so this will have plenty of time to cure before I put it all together.

On top of 100-gallon reef tank:

And of course no DIY project is complete without a few new battle scars :badgrin: