Mike's 300 Double-D

[prop-frags]

hope you know sombody with a truck!!

:lol2: Dunno LB...might have to whip out the mules and wagon!

Mike thanks for all the effort you have put in to this thread it has been very helpful. You have one hell of a fine wife after all the destruction of your fine home with the last freak accident most would have said over my cold dead body yours said lets do it better,please give her a hug for me.:thumbsup:

OH yeah - I am the luckiest man alive; I'm crazy about her! And despite the fact that all this has been very trying, she's still committed to making this a true "Phoenix project!" Thanks for your wonderful remarks.

Looking great! Thank you for all your help with our stand!

Anytime Red! I can swing by there tonight after work if you want - we'll give you a call when I get home.

Question: those 2x6 spans, are they all supported on the corners? It looks like only one of the two on each corner has a support going to the floor.

Great eye, Chris. The back corners have only the 2x6 legs supporting the outside spans. Given all that we have read about the strength of these members on their end (a 2x4 supports > 9 tons), we were comfortable with this design. The rationale is that the 2x6 spans are glued/screwed together (essentially creating a single beam), so there really wouldn't be much additional necessary support underneath the inside span. Should we revisit this?

 

[crvz]

Great eye, Chris. The back corners have only the 2x6 legs supporting the outside spans. Given all that we have read about the strength of these members on their end (a 2x4 supports > 9 tons), we were comfortable with this design. The rationale is that the 2x6 spans are glued/screwed together (essentially creating a single beam), so there really wouldn't be much additional necessary support underneath the inside span. Should we revisit this?

Ah, ok. I didnt know they were glued. I know that the loading of the legs wasnt an issue, but if you were hoping for the 2x6 not to bend/bow it would have needed the support at the end. But with the glue, you should be fine. I went ahead and stuck another 2x6 leg under my 2x8 span, but everything is also glued together.

If you just had screws, then you should probably revisit it. If you have glued it all together properly (what kind of glue did you use, and did you brush it or roll it on?), it should be fine.

 

[prop-frags]

there is one suggestion I would like to make: Put a solid top on that stand, and drill oversize holes for your bulkheads penetrations. Then put a piece of foamboard - not the white beadboard, but the pink or blue brand of extruded foam on the stand top and glue it in place.
The solid top can be plywood, or structural OSB - and will lesson any potential of problems such as you have experienced
This method has worked for me numerous times thu the years. And - as for the solid top...it is how the tank manufacturer makes their stands. The must be a reason for that!:beer:
Cheers!
T

I agree about putting some type of solid top on the stand. Looks great though! Glad you were able to save the beautiful cabinets and stone top.

Guys, I meant to come back to this a couple of nights ago, but have been busy with the electrical work. Thank you both for this advice and feedback. Let me ask you though, is it truly necessary? My question is based on this - in order to accommodate this suggestion, we would have to do one of two things:
1) take the stand apart and lower it by precisely the thickness of the plywood top, or
2) cover the stand, and the surrounding cabinets with the same thickness of plywood

Why? Because the tops of the cabinets must be exactly the same level as the top of the stand for the quartz counter tops to go back in place.

 

[teesquare]

Well, I would defer the manufacturer's stand design. They use a solid plywood top to:
1. add rigidity to the structure - which you do not need...*BUT*...
2. It also will alleviate any un-evenness, or any high or low spots in the 2x framing-...*especially* when....
3.you add in the foam under the glass.

I recognize it is a pain for you to add plywood to the entire top, including the side pieces - but, if it were mine, - I would do it. I have done it to my own, and for clients that have open top stands. I just consider inexpensive peace of mind.
HTH
T

 

[gtaylor67]

I also agree with teesquare, I have the factory tank sitting in my home and I believe the Plywood on the bottom of the tank is about 1" think not half. Maybe that would help with support. Sorry for your losses. But looks like your coming back stronger... Thanks

 

[rick s]

I am not experienced in large tanks, and I have not researched this subject, so this is just a thought. . .

On any of the smaller sized tanks I've seen, there is a bottom frame. That bottom frame is molded on all the outside edges to extend below the rest of the frame. In-other-words, If you put one of those smaller tanks on a piece of plywood, The only thing that is touching the plywood will be the perimeter outside edges. The entire "insides" of the tank/frame will not touch the plywood. So it appears to me that having a complete solid (plywood) top would go unused (from a horizontal structural stand point), as none of the tank or frame will touch it. Again, at least on the "smaller" tanks that I've seen.

Again, I'm just thinking out loud. . .
Foam boards:
Again, if your large tank sits on a frame, and if only the perimeter edges of that frame actually touch the "stand:" If the tank is designed to have only the outside edges rest on the stand, and there are no supports or "feet" built into the "insides" of it to rest on a solid top stand, then the bottom glass panel has obviously been designed to "free float" across the entire span of the bottom glass panel. I have always wondered: If you put foam board under all of it, and the pressure of the bottom frame sinks into it somewhat (as suggested): As the tank's frame sinks into the foam, and the bottom glass panel starts to push against the foam, you'll now have pressure on that glass panel (where it wasn't designed to have pressure put on it).

Anyway, the best answer to this issue is what does the tank manufacturer say? They're the ones that designed the tank. They will obviously know what they recommend, or do not recommend. If you do the wrong thing, you could have warranty issues.

Just thinking out loud. . .

 

[teesquare]

I had my recommendations approved by the head of engineering and manufacturing for Perfecto before doing what I suggested, on my own tanks Rick. I don't take lightly what you are saying, and it it good reasoning that you are using in thinking about these issues.

The critical aspects are the thickness of the foam - it cannot be thicker than the "void" under the tank bottom pane and the surface it sits on. And it needs to not be the white really soft stuff. Use the extruded blue or pink brands.
The foam compresses too, but it helps to prevent point-load stresses in the bottom pane. Like where you have a lrge rock pile, and maybe a smaller diameter load bearing rock in that pile at the bottom. The supporting foam merely "stretches" the point loads out, re-distibuting the load so it becomes more manageable by the glass, and silicone.
The free-floating bottoms are not as common in big tanks as they used to be. There are different opinions on at what water column height/gallonage they should not be used.

As for doing the "wrong thing"....that covers a lot when we want to have tanks like we do! With many manfacturers if you request one hole other than their norm - no warranty. Or if you do not use their stand - no warranty.

HTH

T

 

[mlb75]

Well I know it's a bit late but I'm so sorry to hear of your catastrophe but am glad things are coming back together.

Since I've got a very similar setup to yours it's definitely made me look again at my stand and the rest of the setup. The only thing that makes me sleep a little better is that mine is on a slab and the stand is much closer to what your new one is. It would still be nice to know the root cause of your leak but like you've said I don't expect you'll ever know that.

Keep up with the updates, your build has been very informative.

 

[crabby10]

mlb75: Our 250 DD leaked the same week and neither of us know the root cause...

teesquare: I have a question about the foam. Maybe we both need it.. How do we know the thickness to use? I would think using too much as far as thickness could be a problem. After measuring the thickness from the boards to the glass, its a half inch. Now, using a half inch of foam should alieviate any pressure differencial. Also it should equalize the pressure on the support around the tank as well as the bottom of the glass. right? Or does it need to be greater than half an inch?

Prop-frags: you have a GREAT stand now, but now is the time, if we are going to do this foam thing...I think you are set with your new stand,(It is da bomb!) but you don't want this thing to leak again!! I agree, it will be a huge job because of your countertops. The foam may not even be needed.

Personally, I think the tanks are build to have all the weight distributed equally around the rim. (I am not an expert) However, how do we know it is really equal after you put the tank on the 2x4s? The foam should solve any differencial if installed properly.

 

[teesquare]

The foam needs to meet the bottom of the glas - but not too much more than that. You do not want it really pushing upward on the glass. Just the glass resting on it.

I have - in th elong past - used the white foam board at thicker than the actaul vertical distance between stand top and bottom of glass - but I don recommend it any more. it is to "fickle"...Not an even density product like the extruded foam.
And - you are right - the foam is the ultimate stress equalizer.
T

 

[Taqpol]

I think this was brought up in Will16's thread awhile ago and it made sense to me for people using plastic rimmed tanks. What about putting the extruded foam directly on to the 2x6's of the stand and then setting plywood on top of the foam? This way you still get the cushioning/leveling effect of the foam but there is nothing pushing upwards against the bare glass in the center of the tank.

Of course, if Teesquare has talked to Perfecto and they suggest the foam to go inside the outer edge trim, I would definitely go that route.

 

[teesquare]

Let me clarify - When I talked to Perfecto - they were iffy about - until I explained - in the same degree of detail I have done here.

But, as for placing the foam on the frame of the tankstand....it is better than not, IMHO. But, as you can tell - I am pretty convinced about the use of foam being best over a solid top.
Because the frame open tank stand depends 100% on the frame and the tank trim - and I like more assurance than that. That is all. I am certainly not trying to make Mike and Terry want to buy Rogaine over this issue. Nor do i want anyone else reading this think that "this is the only way". It's part of reefing folks. We all tend to do what makes sense to us as indivduals, and really - should not feel stressed about a sugestion.
Merely a suggestion that has helped me for quite a few years. My apologies for taking up too much of Mike and Terry's time with this.
T

 

[crabby10]

well said. thanks

 

[prop-frags]

Thanks again everyone for the great dialog on the stand!

Tee, from your build thread, you indicate that you're using the factory stand. Is there anything special about it, or are you using the stock 300DD stand? Can you provide some pics/details about it's construction? I really wish for the benefit of this community that Perfecto would weigh in on this topic; many of us - their customers - would benefit from their specific recommendations on what should/should not be done in terms of safely supporting these big DD tanks.

 

[teesquare]

Mike there is abit of "duality" in my support of, and belief in the Perfecto products.
It is this: The stands, as they are from the factory will support the tank. Of that there is no real doubt...as long as they situation is a "stock" tank from their normal catalog.

But - being the anal retentive and slight over-engineering sort I am - and because no tank I do- fits the "norm"......

About the above described conversation w/Perfecto. Are they wrong, and am I right...? No, I don't look at it that way. Rather I think of it as using whatever I have at my disposal to just make "good"..."better".

If any wish to look at all of the pics of how I over-built my own personal stand, you will find them at: www.photobucket.com user name: teesquare1

Please let me know how I can help.

T

 

[mlb75]

Not to be a naysayer or overly negative but my two cents...

The factory stand is IMHO flimsy and in no way what I would consider enough for one of these tanks. Being that as it is and the fact that they still will stand behind that combination resolutely it must truly be way more than enough. (an interesting data point since it has nothing greater than a 1x supporting it)

To me over engineering with fourteen (yes I'm being facetious) of different layers of wood and foam is over engineering things and not truly addressing the actual problem just a symptom and is not the way to go. Being in the business I am while being trained as a mechanical engineer I see it all the time.

Bottom line while adding layer after layer of foam and or wood to the top of the stand can't hurt anything since it's absent in the factory stand (which they will stand behind) points to the fact that it's not needed. Sorry but I'm not ready to believe that the tank needs the extra bracing or support. If it wasn't strong enough from the factory for 99.999% of the installations out there they wouldn't mass produce them, it just wouldn't be profitable for a large corporation. Granted there are always manufacturing defects and or special situations which is what this most likely is.

Having said all that one thing I'd be interested in is in which direction the floor joists were oriented in regards with the tank. Since you've already beefed them up it shouldn't be a problem again but could easily have been the culprit.

 

[teesquare]

Mike (MLB75)
The only reason I doubled the top on mine - is because there are 14 holes in it, and the 2 rear corners were cut out from the facory, as a square of parrox 4''x4''. It is not possible to give you a perspective shot of that, I forgot to take one.
So, based on the removal of material from the factory top, I doubled mine.
Because the factory stand consisted of only a plywood box, I wanted more "shear wall" strength vertically, and horizontally. Without re-designing, or building from scratch - that meant increasing the surface contact area between structural members, and the use of glue and screws. After all, it is a less than perfect world

And the foam - well...we have worn that discussion out.

And, as in most of my earlier posts on this subject, I do not believe in absolutes. I do however believe that most items manufactured in a very competitive market must be built down to a price point. No judgement - just economics that apply to all things.
So, for me it is very much like the tank bottom euro-bracing. Necessary - no, it is not. Beneficial? For me it has been for more than 12 years ( My 360 cichlid tank). As well, over a dozen other tanks I have drawn and had built for freinds and clients - not ( knocking on my head:hmm5: - no leaks) That could change today, but thus far, it is the best insurance for tank bottom seal seal integrity.
And like the tank stand modifications, it cost little to do.

On a different but - maybe interesting subject.....
There are some mis-conceptions in the marketplace, about the physical properties of different materials, and one of them is silicone. It is common to see 500-600% tensile elongation numbers. ( which is one measure of the materials cohesion, or tear resistance) So, can we assume that means the given material has comparable gap-bridging capabilities? No, not even if it has higher comparative kPa for adhesion. Why?
It is because of HOW the manufacturer tests the silicone. It is a narrow strip that is pulled from either end of it's length But - that does not really apply to aquarium building, or the forces/phsics invilved therein - unfortunately.

Just some pre-coffee ramblings....

T

 

[prop-frags]

Mike there is abit of "duality" in my support of, and belief in the Perfecto products.
It is this: The stands, as they are from the factory will support the tank. Of that there is no real doubt...as long as they situation is a "stock" tank from their normal catalog.

But - being the anal retentive and slight over-engineering sort I am - and because no tank I do- fits the "norm"......

About the above described conversation w/Perfecto. Are they wrong, and am I right...? No, I don't look at it that way. Rather I think of it as using whatever I have at my disposal to just make "good"..."better".

If any wish to look at all of the pics of how I over-built my own personal stand, you will find them at: www.photobucket.com user name: teesquare1

Please let me know how I can help.

T

Ahh very informative!! Thanks T. We really have scoured the web looking for detailed pictures of the stock stand and came up empty. Your pics helped immensely. There were a few key things that we were hoping to discern about the factory stand design:
1) materials used for structural members (looks like 1" ply)
2) design, particularly as it applies to structure vs cosmetics (looks like lateral beams and vertical supports are all 1" ply, including a fairly wide center support post for the front and back, and "L shaped" corner supports).
3) the design for the top (looks like 1" ply again with rectangular holes cut in the rear corners for the overflow plumbing, but nothing special about outside "rim" where the tank frame actually sits)

We are thinking hard about all the input and feedback given here - and really appreciate the honest opinions you all are sharing. There certainly is merit to the argument about the Perfecto warranty and the stock stand... they simply couldn't afford to have $2,000 tanks busting all over the country due to an insufficient stand. Obviously, they put all their engineering prowess behind the design of that stand and ensuring that it hits the sweet spot of low cost of production vs. strength.

Similarly, the bottom plate glass of the DD tanks is designed to support a reef aquarium application without creating any problems. 3/4" glass is hefty, and if it had any significant risk of deflecting under typical load scenarios, they would either up the thickness, or include some bottom cross-bracing of some sort, or both.

Regardless, as T points out, this all boils down to safety. The stock tank and stand provide a certain level of safety, and unique applications alter that calculation. Our own experiences create different levels of safety expectations and tolerance, and so we either accept the "stock safety level", or we make modifications to make things more safe.

All of your input help to shape and inform those decisions. Keep them coming.

 

[teesquare]

Mike - I just measured the plywood thickness - it is 11/16'' thick, or "metric 3/4'' equivelant"

 

[prop-frags]

Having said all that one thing I'd be interested in is in which direction the floor joists were oriented in regards with the tank. Since you've already beefed them up it shouldn't be a problem again but could easily have been the culprit.

Mike,
The tank sat perpendicular to the 2x10 floor joists w/the back portion of the tank sitting above a main load-bearing girder (3x laminated 2x10's and cement blocks). Here's a pic of the original structure:

<a href="http://www.flickr.com/photos/terryl93/5031809888/" title="fw 532 by terryl93, on Flickr"><img src="http://farm5.static.flickr.com/4148/5031809888_d44302ae2a.jpg" width="500" height="332" alt="fw 532" /></a>

Could the floor have flexed? Possibly.

Could the stand have flexed? It's possible. One thing we discovered after the fact, was the horizontal 2x4's front and back were not sitting on a vertical post even on the corners, but were held up by a deck screw. Have to say, that was a bit shocking to see and had a lot to do with our decision to rebuild the "guts" of the stand from scratch.

We also noticed that there were areas in the tank where the silicon could easily be peeled back from the glass w/your finger and that it was for lack of a better word, "meally" and fell apart. So, was there a problem w/the silicon itself or in the way the glass was prep'd? There's no way for us to know.

Since we don't know exactly what happened, we've tried to cover all aspects (floor support, stand structure, and eurobracing) to ensure we don't wind up in a similar situation again (and I can sleep at night ).

We appreciate all the input from everyone and keep it coming... :thumbsup:

-Terry :fish1:

ps... and Tee, I like your suggestions regarding the plywood top and foam board.