Karim's 1500gal dream reef

[karimwassef]

Ok.. buoyancy on a 3" x 4" x 48" air box = 576 in3
Force (lbs) = 0.037 x volume (in3) = 21lbs



Wow... should have done the math before getting too excited.

Bigger box? Lubricate the o-rings more? Shave down the PVC slightly?

Probably all of the above

 

[karimwassef]

The 18" depth is getting in the way. The height budget is like this:

Pipe fully extended = 9" (cut and shaped to fit)
Air box = 3"
Overflow sides = 6"

I guess I'll have to go wider and longer on the box to make it float better.

I think my width is actually 6" (going off memory now), so that's a mistake in our favor.

Making it 8" and pushing the overflow to be 6' would be 64lbs.. doesn't feel right...

 

[NeverlosT]

to alter the height of the drain pipes, it might be easier to have flexible pipe mated to rigid standpipes on each end, then you don't have to worry about the telescoping members failing/biofouling (I am not sure that those are intended to be repeatedly cycled, I think they are just meant to be adjusted once and left).

Regarding lifting and lowering the weirs... I wonder if you can go old school on the issue, and rig up an elongated paddle wheel to the back of the weir, overflowing water spins it, and a few gears result in the weir climbing or descending? Trying to think of using the water movement itself to actuate the mechanism, like some of those rollermats do I think.

The other thing is, maybe leave the weir on the outside stationary just with really deep teeth, then you just move up or down a thin inner wall that either exposes more or less of the weir teeth. Then you might be able to reduce the moving mass.

 

[karimwassef]

I've considered the flexible pipes but these 2" drains will be carrying 2000gph flow each! I also have a horizontal run that varies from 3' to 6'... any additional bending will make them useless imo. I won't even use hoses because of the transition losses and the additional impedance from the hose surface. I'm using flexPVC or preferably pre-shaping rigid 2" PVC into the required shape to avoid any couplers. The flow through the PVC extenders will be the worst of it but at least it's perfectly vertical and the extenders are much bigger than 2" in the overlapping sections.

 

[karimwassef]

I've used the telescoping fitting for over a hundred thousands insertions over the last three years. The link I posted above shows the last cleaning I did.

They are way overdesigned and incredibly cheap for the flexibility they offer in DIY.

I used one for continuous 360degree rotation at 1RPM for two years before trying a digital D.C. pump controlled flow diverter.... I took it apart and the seal and o-rings were unchanged. The only wear was to the coupling from the motor shaft to the PVC... the motor also suffered with salt spray but it still works.

 

[karimwassef]

The rotational force is a lot higher than the insertion force.

 

[karimwassef]

ok.. got home.. made measurements...

and WOW.. what was I smoking when I was 50lbs??

I admit it when I am off and I was way way way off.

I tested both the 1" and 2" extensions for contractions and extensions.

1" contraction (insertion) force = 3.5lbs
1" extension force = 5.5lbs

2" contraction (insertion) force = 7.5lbs
2" extension force = 8.5lbs

This is at the start.. over repetitive insertions and extensions, they both normalized to the same for in and out: 1" ~ 3lbs ... and 2" ~ 8lbs

So.. 3 of the 2" would at most be 30lbs without any modification. So the 6' x 8" x 3" air box would be 2x the force needed to raise the platform...

given that I'm not accounting for all other variables like the force of the water flowing into the overflow and partially filling it as it attempts to rise, etc, it should be ok.

 

[jccaclimber]

ok.. got home.. made measurements...

and WOW.. what was I smoking when I was 50lbs??

I admit it when I am off and I was way way way off.

I tested both the 1" and 2" extensions for contractions and extensions.

1" contraction (insertion) force = 3.5lbs
1" extension force = 5.5lbs

2" contraction (insertion) force = 7.5lbs
2" extension force = 8.5lbs

This is at the start.. over repetitive insertions and extensions, they both normalized to the same for in and out: 1" ~ 3lbs ... and 2" ~ 8lbs

So.. 3 of the 2" would at most be 30lbs without any modification. So the 6' x 8" x 3" air box would be 2x the force needed to raise the platform...

given that I'm not accounting for all other variables like the force of the water flowing into the overflow and partially filling it as it attempts to rise, etc, it should be ok.

I was going to ask how you were exerting 50 lbf on that thing by hand and calling it easy, but this makes a lot more sense.

I think that the transition from rigid pipe to flex hose is going to be one of the smallest losses in your system, but if you can do it all rigid and trust it, by all means do so. It sounds like they've been good enough so far.

Don't forget the weight of the box in your calculations, especially if it is glass rather than acrylic.

Max flow through a 2" pipe is going to depend on joints, length, and drop (head pressure). There should be an online calculator somewhere, if not it's easy enough to estimate.

 

[karimwassef]

ok.. the siphon formula (ignoring all impedance) is ~ 147 x sqrt (5.36 x drop ) x diameter^2

where the drop and diameter are in inches... so drop = 24", and diameter = 2" so ~ 6700gph per pipe in full siphon.

So three pipes with an overflow should be capable of handling ~ 27,000 gph

Again - this is ignoring the fact that the siphons will not be perfect (air complicates things) and the pipes have horizontal runs.

 

[karimwassef]

I was going to ask how you were exerting 50 lbf on that thing by hand and calling it easy, but this makes a lot more sense.

as I said ... what was I smoking??? but thanks for trusting my extra-super strength!!

Don't forget the weight of the box in your calculations, especially if it is glass rather than acrylic.

I decided early on on a simple design rule. If it doesn't move, it's made of glass. If it moves, it's made of plastic. This applies to ANY moving parts. So while the baffles around the overflow are glass, the overflow and airbox move = acrylic.

Max flow through a 2" pipe is going to depend on joints, length, and drop (head pressure). There should be an online calculator somewhere, if not it's easy enough to estimate.

I got the full siphon (max possible), now I need to account for the horizontal runs and bends. THe real design decision is whether I need to run a fourth pipe to be sure.

Keep in mind that the maximum return flow is also gravity fed through 6 pipes at 2" PVC but at a 4' drop... vs. the drain is 4 pipes at 2" PVC with a 2' drop.... but I don't expect that all the return lines will be on at once.

Of the 6 returns, 4 are controlled flow (maybe oscillating but not open full blast), and 2 are surge (can run full blast).

but since it is theoretically possible for all 6 to be open at the same time ... that would run at 60,000 gph and totally overwhelm the 4 drains...

 

[karimwassef]

I am still struggling with my tank height budget though... Here's the 2" extension

<a href="http://s1062.photobucket.com/user/karimwassef/media/E433284A-5FA6-478D-890D-3D2ADAB09685_zpsxsh9iiju.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/E433284A-5FA6-478D-890D-3D2ADAB09685_zpsxsh9iiju.jpg" border="0" alt=" photo E433284A-5FA6-478D-890D-3D2ADAB09685_zpsxsh9iiju.jpg"/></a>

End to end it's 12".

I think I need 3" from the top of the tank to the weir lip. 1/2" to 1" for normal flow and 3" for the surge (a controlled surge) and 3" for the air chamber and 9" for the shaved down extension pipe when fully extended, and the overflow sides = 6"... that's 21" and I only have 18".

I could steal it from the bottom channels.. or I could increase the tank height by 3"... or I could find a way to incorporate the extension pipes into the air chambers so the pipes so they share space.

 

[jccaclimber]

I don't see why they shouldn't share space, they won't displace all that much air. That said, I'm still for the plywood "bottom" being a couple inch deep chamber. That would get you your 3".

 

[karimwassef]

I don't see why they shouldn't share space, they won't displace all that much air. That said, I'm still for the plywood "bottom" being a couple inch deep chamber. That would get you your 3".

couple inch deep chamber? hmmm you don't appreciate the dark zone enough...

It would need to handle the circulating flow from the two top channels. with 2/3 the area, it's already going to be experiencing 50% more fluid flow to keep the loop balanced.

<a href="http://s1062.photobucket.com/user/karimwassef/media/Designs/0011_zpsycxnq3pu.png.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/Designs/0011_zpsycxnq3pu.png" border="0" alt=" photo 0011_zpsycxnq3pu.png"/></a>

 

[jccaclimber]

couple inch deep chamber? hmmm you don't appreciate the dark zone enough...

It would need to handle the circulating flow from the two top channels. with 2/3 the area, it's already going to be experiencing 50% more fluid flow to keep the loop balanced.

< snip >

I'm saying to make the entire tank taller, so your glass height is the same, but the floor is recessed giving you more interior space.

 

[karimwassef]

oh! You mean to change the flat floor with an indent to a shallow box base for the tank?

Interesting option... more complex... but it would give a few more inches to the top area.

The compromise (other than complexity) is that the floor of the dark zone would be difficult to see and that's where I expect the coolest things to be.

 

[karimwassef]

Ok. Combining the extension into the bubble chamber makes everything fit nicely.

I can even go 8" deep on the air chamber now. 8" x 8" x 48" displaces enough water to generate 114 lbs of lift! Now I need to make sure the wire can handle that strain without slicing through the PVC piping I'm running it through.

Now, it's 2" head + 5" overflow + 8" chamber + 3" extension = 18".

The only penalty is that I can't removed the extensions for regular maintenance. That means I need to build two overflows and keep one in backup. In case of an issue, I'll need to shut the drains (and loop) down and then remove the full assembly (legs, chamber and overflow) for replacement. It's a small unit so shouldn't be too expensive.

I will need to add a union coupler at the bottom.... darn it... now I need two inches again!!

Since all this is submerged, I was going to use uniseals in the false floor anyway (less drag).

I'll have to cut the extender back but I think I can make it work.

 

[karimwassef]

Oh... and the idea of a pasture for my fish to graze in... a water bridge?? I can lead my fish to algae in the solar scrubber then back to the reef and gate them out.

Ok. That's too fancy even for me... but just thinking out loud.

 

[Darthv247]

haha. the tangs woukd never come back to the barn

 

[karimwassef]

the scrubber is just a big open tub... no rocks to hide in... I can just chase them back up the bridge... like a predator.

 

[jccaclimber]

That might bring out the tang police.