Drop off reef design - Starphire

[dave.m]

The big question is if 0.5" will work for the L sides.

Whatever height you go with, the long part, or "toe," of the L is going to determine your glass thickness for the whole side pane. The effect of water weight is determined by how high you pile the water, not how wide the tank is. I have had tanks up to 36" tall using 0.5" low-iron glass, but that was with three inch wide euro-bracing, both top and bottom. The top brace prevents deflection of the pane, which strains the side seams. The bottom brace prevents blow-out along the bottom seam where most large tanks fail.

Dave.M

 

[karimwassef]

maybe a secret PVC fish tunnel between the deep section and the bottom of shallow section - exiting from inside a rock?

I worry about some fish getting cornered in the deep section and not being able to get back out to the shallow open water.

 

[karimwassef]

Whatever height you go with, the long part, or "toe," of the L is going to determine your glass thickness for the whole side pane. The effect of water weight is determined by how high you pile the water, not how wide the tank is. I have had tanks up to 36" tall using 0.5" low-iron glass, but that was with three inch wide euro-bracing, both top and bottom. The top brace prevents deflection of the pane, which strains the side seams. The bottom brace prevents blow-out along the bottom seam where most large tanks fail.

Dave.M

I agree that depth determines thickness. That's why I can go with 0.5" on the shallow section.

But... when you have really long spans (like 108"), that becomes a factor too. So that's where the bracing helps. That's why I added a double bottom rim of 0.5" thick plates that are 3" and 2" wide.

The risk is at the top, but that's not where the pressure is so I think I'm ok with double stack 0.5" at 1" wide? The other risk is also at the deep face with the most pressure, that's why I went with 0.75".

I rounded the L inside corner with a 2" radius (4" hole). That complicated things, but I agree that that's the highest stress point.

 

[karimwassef]

giving props to Flo's tank - check out the link above to see the rest.

I just LOVE these pictures

<a href="http://s774.photobucket.com/user/flofromaustria/media/Stufenbecken/20151213/DSC_2623_zpsn0mspef1.jpg.html" target="_blank"><img src="http://i774.photobucket.com/albums/yy27/flofromaustria/Stufenbecken/20151213/DSC_2623_zpsn0mspef1.jpg" border="0" alt=" photo DSC_2623_zpsn0mspef1.jpg"/></a>

<a href="http://s774.photobucket.com/user/flofromaustria/media/Stufenbecken/20151213/DSC_2619_zpscuxkjvzq.jpg.html" target="_blank"><img src="http://i774.photobucket.com/albums/yy27/flofromaustria/Stufenbecken/20151213/DSC_2619_zpscuxkjvzq.jpg" border="0" alt=" photo DSC_2619_zpscuxkjvzq.jpg"/></a>

I imagine mine being a wider version... I hope it's as successful.

 

[karimwassef]

So Flo - how DO YOU get to anything on the bottom of the deep side?

 

[mav3rick478]

I'm not familiar with tank building but is it possible to use plexi for the bottom L shape to cut down on weight but have the added strength in a thinner sheet as opposed to glass and to have the ability to be one piece that is molded? My thought process comes from automotive for example forged aluminum wheels can be thinner and stronger because they are one solid original piece. Is it possible to build with a mixture of glass and plexi? Sorry if my question is way out in left field and ridiculous.

 

[karimwassef]

It is off topic, but not ridiculous. Unusual shapes and large tanks are easier with acrylic.

But as I answered earlier, I'm not a fan of the scratches they get, the extra thickness required and the bulge that develops over long spans.

Glass is siliconed together. Plastic is glued. Silicone actually adheres to glass so it can both seal and form a mechanical bond. Silicone may seal acrylic like a gasket, but there's no adhesion. Similarly, acrylic glues don't work on glass... The methods of bonding and sealing have different properties and mechanics, so mixing is difficult.

It's possible to mix glass with acrylic and even PVC, but they can't be glued or siliconed only. The build needs to use both ... in an engineered structure. So, not impossible but harder.

The L shapes have been made in glass. If I just used 1" glass, the discussion would be moot. But I'm looking for the most cost efficient design with a reasonable safety margin.

 

[b22]

That looks awesome.

 

[FloformAustria]

good morning!

i´m still thinking how this mixing of different thick glass will look and how it has an impact on cleaning the glass. somewhere there has to be a little step in the sideplate...

how do i get to the deep bottom you ask?
taking of my shirt and little bit of standing on my toes then i can reach it but only because its 55cm long...

 

[karimwassef]

The only visible change is glass thickness is the deep end at 0.75" vs the L sides at 0.5". I don't think it'll be noticeable.

At 42" on the deep end, even with 3" of sand, that's a 39" span.

My reach is probably 26-27". I have 36" tongs/grabbers but there's no feedback or strength to their grip.

 

[karimwassef]

I have a lip between the two zones for the sand to stay in place.

I plan on three separate magnets given the span of the tank faces and different thicknesses.

 

[karimwassef]

good morning!

i´m still thinking how this mixing of different thick glass will look and how it has an impact on cleaning the glass. somewhere there has to be a little step in the sideplate...

how do i get to the deep bottom you ask?
taking of my shirt and little bit of standing on my toes then i can reach it but only because its 55cm long...

Oh! I think you mean my first drawings. I've gone to a uniform 0.5" on the L based on the feedback here and reducing the depth and length of the deep zone.

Also added bracing at the bottom and a radius to the corner.

 

[NEReef]

This is one of the coolest drop off tanks. The guy is from the UK his tank is ~1200 gallons.

Talking about PVC.... would it be cheaper to just make the entire bottom out of PVC? Since it will be covered by sand it wont matter if it scratches?

Also since it is your money and not mine I would say make the drop off as big as you can. That is going to be the real focal point of the tank. Yes it may make life more difficult but a tall cascading reef into the drop off would look wicked awesome!

 

[karimwassef]

Yes. I saw that awesome build on another site. He's using the fact that it's built into a wall with the back being solid to use steel framing for support.

I want a peninsula open top so that really changes what I can do.

Also- money is A REAL object - so back to an economically optimized design.

This won't be cheap but I have a whole sunroom / greenhouse to build around it... So it can be expensive, but must be optimized for maximum benefits.

 

[karimwassef]

Oh.. He's got the most painful of access problems. Ceiling only access!! + built in design restriction!! + insane depth!!

After the challenges with my built in tank, I won't go there again

 

[karimwassef]

Here's an example of how painful this access issue is. I have seiously considered modifying toy RC submarines with grips so they can perform search and rescue operations in the tank!! Sounds ridiculous but when you're watching a beautiful frag dying right before your eyes and can't get to it without wrecking a whole bunch of colonies, you go 'wild' with what if.

I eventually concluded that the RC subs are too clumsy and would cause as much damage as my arms.

Then! I considered equipping my cleaning magnets with telescoping arms and little grippers connected by fishing line to the surface... Desperate, huh?

Anyway... The frag died before I could dig further into the idea.

 

[karimwassef]

PVC bottoms have been used to save money, but it's not that much cheaper if you're just using 0.5" glass.

My current sump is actually plywood, epoxy and plexiglass. It's 24" x 24" x 60". I used 1/4" plexi but that's because they're small windows <24" wide. It works but I don't want the window look.

This is ugly rear side view of my current setup. You can see the plywood sump on the bottom

<a href="http://s1062.photobucket.com/user/karimwassef/media/AD7B7DA9-CE1E-4764-9419-33F713DC8B30_zpsbna4toio.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/AD7B7DA9-CE1E-4764-9419-33F713DC8B30_zpsbna4toio.jpg" border="0" alt=" photo AD7B7DA9-CE1E-4764-9419-33F713DC8B30_zpsbna4toio.jpg"/></a>

 

[FloformAustria]

I like the idea of RC submarines!! Not that bad of an idea!

Pvc bottom is maybe not that bad...?

 

[karimwassef]

so I'm showing the back, I'll show the front for balance

<a href="http://s1062.photobucket.com/user/karimwassef/media/602396F7-DEAD-435F-B350-548A5D393D51_zpstykpbmqu.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/602396F7-DEAD-435F-B350-548A5D393D51_zpstykpbmqu.jpg" border="0" alt=" photo 602396F7-DEAD-435F-B350-548A5D393D51_zpstykpbmqu.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/2E4F587E-7E73-4DB1-BA80-374C8E43767B_zpsbnub1lcy.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2E4F587E-7E73-4DB1-BA80-374C8E43767B_zpsbnub1lcy.jpg" border="0" alt=" photo 2E4F587E-7E73-4DB1-BA80-374C8E43767B_zpsbnub1lcy.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/5374D3FE-3DA1-417D-8E2B-BA83D810BBC2_zpslmodyc9k.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/5374D3FE-3DA1-417D-8E2B-BA83D810BBC2_zpslmodyc9k.jpg" border="0" alt=" photo 5374D3FE-3DA1-417D-8E2B-BA83D810BBC2_zpslmodyc9k.jpg"/></a>

 

[karimwassef]

I like the idea of RC submarines!! Not that bad of an idea!

Pvc bottom is maybe not that bad...?

maybe. I haven't given it much though even though AGE is actually based in Garland less than 15 minutes from my house. The last time I talked to them, they were 2x the cost of having a glass tank shipped to me.

I did find this site:

http://reefcentral.com/forums/showthread.php?t=1825679

I think the idea is to create a groove in the thick PVC so the glass can seat into it and then use silicone to seal.