Reef Central Online Community

Go Back   Reef Central Online Community > General Interest Forums > New to the Hobby
Blogs FAQ Calendar Mark Forums Read

Notices

User Tag List

Reply
Thread Tools
Unread 09/11/2019, 11:21 PM   #1
iamborg
Registered Member
 
Join Date: Apr 2009
Posts: 127
Strength of glass

I am planning to setup a 40G breeder standard Aqueon tank as a reef tank.
The stand I have is a 40G petco metal stand.

The stand is "hollow" on the top, and the tank is only resting on the edges.

If I put sand [40 lbs] and rocks [40 lbs] + the weight of the water, wont the
bottom of the glass tank break under such a large amount of weight?

Also the rocks are not evenly distributed, wont there be pressure points
on the bottom of the glass?

Please advise. thanks.


iamborg is offline   Reply With Quote
Unread 09/12/2019, 01:25 AM   #2
Tastee
Registered Member
 
Tastee's Avatar
 
Join Date: Oct 2017
Location: Sydney Australia
Posts: 277
I would place a layer of plywood on top of the stand, then a layer of foam and finally the tank. I am not an engineer but would expect 9mm/3/8” would suffice. I would personally use 12mm/1/2” to be safe.


Sent from my iPad using Tapatalk


Tastee is offline   Reply With Quote
Unread 09/12/2019, 04:32 AM   #3
mcgyvr
Registered Member
 
mcgyvr's Avatar
 
Join Date: Sep 2003
Location: North Carolina
Posts: 20,050
The tanks and stand are designed to not break under typical usage..
What you describe falls under typical usage..
You do not need to do anything special.

The bottom piece of glass is not resting on the ground and the only thing touching is the black trim piece..

Putting a piece of plywood will make no difference at all. The bottom glass will still be floating off the plywood and the trim perimeter is still the only contact with the plywood surface.. Nothing changes..


__________________
Who me?
mcgyvr is offline   Reply With Quote
Unread 09/12/2019, 06:01 AM   #4
billdogg
Registered Member
 
billdogg's Avatar
 
Join Date: Apr 2008
Location: Grove City, Ohio
Posts: 10,806
Quote:
Originally Posted by mcgyvr View Post
The tanks and stand are designed to not break under typical usage..
What you describe falls under typical usage..
You do not need to do anything special.

The bottom piece of glass is not resting on the ground and the only thing touching is the black trim piece..

Putting a piece of plywood will make no difference at all. The bottom glass will still be floating off the plywood and the trim perimeter is still the only contact with the plywood surface.. Nothing changes..
^^^this^^^


__________________
I'll try to be nice if you try to be smarter!
I can't help that I grow older, but you can't make me grow up!

Current Tank Info: 120 mixed reef with 40b sump, RO 150 skimmer, AI Sol Blue x 2, and a 60g Frag Tank with 100g rubbermaid sump. 2 x Kessil A360w lights, BM curve 5 skimmer
billdogg is offline   Reply With Quote
Unread 09/12/2019, 06:14 AM   #5
Tastee
Registered Member
 
Tastee's Avatar
 
Join Date: Oct 2017
Location: Sydney Australia
Posts: 277
Quote:
Originally Posted by mcgyvr View Post
The tanks and stand are designed to not break under typical usage..
What you describe falls under typical usage..
You do not need to do anything special.

The bottom piece of glass is not resting on the ground and the only thing touching is the black trim piece..

Putting a piece of plywood will make no difference at all. The bottom glass will still be floating off the plywood and the trim perimeter is still the only contact with the plywood surface.. Nothing changes..

Apologies for the bad advice, thanks for the correction @mcgyvr & @billdogg



Sent from my iPad using Tapatalk


Tastee is offline   Reply With Quote
Unread 09/12/2019, 06:58 AM   #6
billdogg
Registered Member
 
billdogg's Avatar
 
Join Date: Apr 2008
Location: Grove City, Ohio
Posts: 10,806
No worries! It is a common misconception. There are two ways to make a tank. You can have a floating bottom. 99% of "standard" tanks with plastic trim are made this way. The other option is to use the bottom pane of glass as the platform on which the 4 sides rest. I would guess that most (if not all) rimless tanks are made in this manner.

When the bottom is floating, all the weight rests on the perimeter of the tank and only the edges (especially the corners) need support. Many people use a piece of plywood underneath them anyway if for no other reason than it will block the light into the sump area if you are going bare bottomed or use a shallow sandbed that might allow some light through. What you DON'T want to do is put anything that is compressible under a floating bottom because if it compresses enough it can press up on the bottom glass and potentially cause the seal to fail. Although some still go this route due to uneven stand tops, it is generally not advised. The reason is that although it will, indeed, compress and appear to even the load, it won't necessarily prevent pressure points that can damage the tank at some point down the road.

On the other hand, if the tank does not have a floating bottom, it will require support across it's entire surface so that the weight of the tank is spread evenly. This is when a solid surface like plywood is mandatory. It is also a good time to consider a thin sheet of Styrofoam or or slightly compressible material is a great idea. It will allow for whatever slight imperfections to be compensated for and prevent pressure points that can easily crack the bottom glass.

HTH!


__________________
I'll try to be nice if you try to be smarter!
I can't help that I grow older, but you can't make me grow up!

Current Tank Info: 120 mixed reef with 40b sump, RO 150 skimmer, AI Sol Blue x 2, and a 60g Frag Tank with 100g rubbermaid sump. 2 x Kessil A360w lights, BM curve 5 skimmer
billdogg is offline   Reply With Quote
Unread 09/12/2019, 08:03 AM   #7
mcgyvr
Registered Member
 
mcgyvr's Avatar
 
Join Date: Sep 2003
Location: North Carolina
Posts: 20,050
Quote:
Originally Posted by billdogg View Post
No worries! It is a common misconception. There are two ways to make a tank. You can have a floating bottom. 99% of "standard" tanks with plastic trim are made this way. The other option is to use the bottom pane of glass as the platform on which the 4 sides rest. I would guess that most (if not all) rimless tanks are made in this manner.

When the bottom is floating, all the weight rests on the perimeter of the tank and only the edges (especially the corners) need support. Many people use a piece of plywood underneath them anyway if for no other reason than it will block the light into the sump area if you are going bare bottomed or use a shallow sandbed that might allow some light through. What you DON'T want to do is put anything that is compressible under a floating bottom because if it compresses enough it can press up on the bottom glass and potentially cause the seal to fail. Although some still go this route due to uneven stand tops, it is generally not advised. The reason is that although it will, indeed, compress and appear to even the load, it won't necessarily prevent pressure points that can damage the tank at some point down the road.

On the other hand, if the tank does not have a floating bottom, it will require support across it's entire surface so that the weight of the tank is spread evenly. This is when a solid surface like plywood is mandatory. It is also a good time to consider a thin sheet of Styrofoam or or slightly compressible material is a great idea. It will allow for whatever slight imperfections to be compensated for and prevent pressure points that can easily crack the bottom glass.

HTH!


^^^this^^^ @Billdog..

I don't even consider it "bad advice".. There is really no harm in doing what you proposed so its not "bad".. Just not needed..


__________________
Who me?
mcgyvr is offline   Reply With Quote
Unread 09/12/2019, 10:02 AM   #8
iamborg
Registered Member
 
Join Date: Apr 2009
Posts: 127
Thank you for the clarification and advise.

This is my first try with a large standard rim tank.
My previous tanks were all rimless and small [8G, 24G], and all of them
have flat supported stand under the bottom; so I was worried.

Thanks again.


iamborg is offline   Reply With Quote
Unread 09/12/2019, 10:05 AM   #9
mcgyvr
Registered Member
 
mcgyvr's Avatar
 
Join Date: Sep 2003
Location: North Carolina
Posts: 20,050
Yep..
Often times "rimless" and other "non-floating" tanks require full support as well as a manufacturer specified padding to maintain integrity as well as warranty of the tank..


__________________
Who me?
mcgyvr is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



All times are GMT -6. The time now is 03:55 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Use of this web site is subject to the terms and conditions described in the user agreement.
Reef CentralTM Reef Central, LLC. Copyright ©1999-2022
User Alert System provided by Advanced User Tagging v3.3.0 (Pro) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.