foam under aquarium - a stupid question

[Carlton Crawford]

Technically no question is stupid. I know this, but for some reason
this one feels like it is.

I've recently acquired a 20 gallon tank. I plan on placing foam
underneath it in order to help support the glass. My question is
this. Do you cut the foam to match the bottom glass or do you cut it
bigger. I drew a pretty little picture to illustrate what I'm trying
to say...hopefully ya'll will understand.

-------------------------------
l l
l cut inside l Or outside the lines?
l the lines? l
l l
-------------------------------

So what's best?

I have lots of questions...hopefully I'll actually ask some of them,
but I've learned to wait and make sure I'm not completely ignored
first. Thus far, it appears this group is really good about answering
questions for us newbies.


Thanks a million (or two if you really need it)

Carlton

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[Charles]

On Tue, 19 Jul 2005 22:03:07 -0500, Carlton Crawford
> wrote:

>Technically no question is stupid. I know this, but for some reason
>this one feels like it is.
>
The foam should not touch the glass, it should only support the outer
frame.
--
Charles

Does not play well with others.

[NetMax]

"Charles" > wrote in message
...
> On Tue, 19 Jul 2005 22:03:07 -0500, Carlton Crawford
> > wrote:
>
>>Technically no question is stupid. I know this, but for some reason
>>this one feels like it is.
>>
> The foam should not touch the glass, it should only support the outer
> frame.
> --
> Charles
>
> Does not play well with others.

Um, yes but this assumes the bottom glass is inside the edges ;~), but if
the edges sat on the bottom, then the question wouldn't be asked, so I
should stop now.

In the bigger picture, perhaps a 20g doesn't really need foam underneath,
but if you insist, then use a thin sheet (so it doesn't slip off from
compressing the material) and leave a little extra around the edges
(useful for smaller tanks with thinner edges)..
--
www.NetMax.tk

[David C. Stone]

In article >, NetMax
> wrote:

> "Charles" > wrote in message
> ...
> > On Tue, 19 Jul 2005 22:03:07 -0500, Carlton Crawford
> > > wrote:
> >
> >>Technically no question is stupid. I know this, but for some reason
> >>this one feels like it is.
> >>
> > The foam should not touch the glass, it should only support the outer
> > frame.
> > --
> > Charles
> >
> > Does not play well with others.
>
> Um, yes but this assumes the bottom glass is inside the edges ;~), but if
> the edges sat on the bottom, then the question wouldn't be asked, so I
> should stop now.
>
> In the bigger picture, perhaps a 20g doesn't really need foam underneath,
> but if you insist, then use a thin sheet (so it doesn't slip off from
> compressing the material) and leave a little extra around the edges
> (useful for smaller tanks with thinner edges)..

I have styrofoam sheet under by 130g tank, on the recommendation of the
person who setup and installed it. It was left oversize, then trimmed
once the tank had settled and compressed the styrofoam. At some point,
I need to cover the edges with black tape, but it's fine as is.

I've never bothered with anything for my 10g tank, as it has an external
metal frame and there is not enough weight inside to flex the glass that
much.

[lgb]

In article >,
says...
>
>
> In the bigger picture, perhaps a 20g doesn't really need foam underneath,
> but if you insist, then use a thin sheet (so it doesn't slip off from
> compressing the material) and leave a little extra around the edges
> (useful for smaller tanks with thinner edges)..
>
I use the 1/2" extruded foam sold as insulation in stores like Lowes or
Home Depot. I cut it just larger than the tank andcover the edges with
duct tape.

The extruded foam is thicker than ordinary styrofoam and you don't get
near the amount of debris when cutting it.

BTW, in model railroading we cut and sculpt extruded foam mountains
and canyons with the preferred tool being a hot wire.


--
BNSF = Build Now, Seep Forever

[John >]

> In the bigger picture, perhaps a 20g doesn't really need foam underneath,
> but if you insist, then use a thin sheet (so it doesn't slip off from
> compressing the material) and leave a little extra around the edges
> (useful for smaller tanks with thinner edges)..
> --
> www.NetMax.tk

I have 1" Blue Styro under my 1000g. It really helps keep the weight on the
base even. I have one 120 that is supported Only at the corners, and has
been that way for 5 years, the other 120, 75 & 55 are on a flat surface all
around w/o foam.

JOhn ><>

[Daniel Morrow]

"lgb" > wrote in message
...
> In article >,
> says...
> >
> >
> > In the bigger picture, perhaps a 20g doesn't really need foam
underneath,
> > but if you insist, then use a thin sheet (so it doesn't slip off from
> > compressing the material) and leave a little extra around the edges
> > (useful for smaller tanks with thinner edges)..
> >
> I use the 1/2" extruded foam sold as insulation in stores like Lowes or
> Home Depot. I cut it just larger than the tank andcover the edges with
> duct tape.
>
> The extruded foam is thicker than ordinary styrofoam and you don't get
> near the amount of debris when cutting it.
>
> BTW, in model railroading we cut and sculpt extruded foam mountains
> and canyons with the preferred tool being a hot wire.

I love model railroading almost as much as fishkeeping - model railroading
is a great way to learn electronics. I used to have a relatively complex ho
railroad setup with some automation (automation of the various accessories
and visual candy is one of my most favorite things about model railroading).
When I get my dream mansion complete with a radio activated collar on every
one of my dogs and one big doggie door with receiver (so the doggy door is
always locked unless the dogs are trying to get in) and when I have the
space afterward (which will be easy with my dream mansion) I will get back
into model railroading. Just my 2 cents on what is pretty much off topic
(sorry where appropriate) here, good luck and later!


>
>
> --
> BNSF = Build Now, Seep Forever

[Dick]

On Wed, 20 Jul 2005 22:12:48 -0500, "John ><>"
> wrote:

>> In the bigger picture, perhaps a 20g doesn't really need foam underneath,
>> but if you insist, then use a thin sheet (so it doesn't slip off from
>> compressing the material) and leave a little extra around the edges
>> (useful for smaller tanks with thinner edges)..
>> --
>> www.NetMax.tk
>
>I have 1" Blue Styro under my 1000g. It really helps keep the weight on the
>base even. I have one 120 that is supported Only at the corners, and has
>been that way for 5 years, the other 120, 75 & 55 are on a flat surface all
>around w/o foam.
>
>JOhn ><>
>


I had never heard of putting styro under tanks when I set up my tanks.
My 75 gallon tank has 100 lbs of gravel and the base cabinet only
supports the tank frame. It has been up for 2 1/2 years. What is the
argument that favors putting styro under the tanks?

I have quit using bio wheels, charcoal and my bubblers. There seem to
be lots of "beliefs" that "ain't necessarilly true" as the old song
puts it.

dick

[George Pontis]

In article >,
says...
> > In the bigger picture, perhaps a 20g doesn't really need foam underneath,
> > but if you insist, then use a thin sheet (so it doesn't slip off from
> > compressing the material) and leave a little extra around the edges
> > (useful for smaller tanks with thinner edges)..
> > --
> > www.NetMax.tk
>
> I have 1" Blue Styro under my 1000g. It really helps keep the weight on the
> base even. I have one 120 that is supported Only at the corners, and has
> been that way for 5 years, the other 120, 75 & 55 are on a flat surface all
> around w/o foam.
>
> JOhn ><>

1", that is realy a lot. If it was a glass tank where all the pressure is around
the edges then maybe the 1" would crush down significantly ?

I think the main value of a compressible material under the tank is to make the
weight distrubution under the tank be more uniform. Since tanks are very flat as
manufactured, flatness problems are almost always due to the stand or furniture
supporting the tank. AGA (All Glass Aquarium) suggested a good method for checking
before the tank is full, which is to see if a business card would slip under the
tank rim anywhere around the perimeter. (If the stand gets distorted much when the
tank is filled it is probably marginal for the job.)

Once the problem is gauged, a piece of spongy material can be put under the tank
to improve a marginal situation. For a rule of thumb I would try something with a
thickness that is roughly comparable, maybe twice the amount that the stand is out
of flat. The padding also has to be pretty soft since the pressure is not really
very high when it is spread over the entire bottom of the tank. Even if it is just
under the rim of the tallest glass tank, the pressure is not even 20 pounds per
square inch - an amount that anyone can reach squeezing something between their
fingers.

If the surface is strong enough but not very flat, then I would use a piece of
3/4" plywood under the tank and sponge foam under that.

[David C. Stone]

In article >, Dick
> wrote:

> On Wed, 20 Jul 2005 22:12:48 -0500, "John ><>"
> > wrote:
>
> >> In the bigger picture, perhaps a 20g doesn't really need foam underneath,
> >> but if you insist, then use a thin sheet (so it doesn't slip off from
> >> compressing the material) and leave a little extra around the edges
> >> (useful for smaller tanks with thinner edges)..
> >> --
> >> www.NetMax.tk
> >
> >I have 1" Blue Styro under my 1000g. It really helps keep the weight on the
> >base even. I have one 120 that is supported Only at the corners, and has
> >been that way for 5 years, the other 120, 75 & 55 are on a flat surface all
> >around w/o foam.
> >
> >JOhn ><>
> >
>
>
> I had never heard of putting styro under tanks when I set up my tanks.
> My 75 gallon tank has 100 lbs of gravel and the base cabinet only
> supports the tank frame. It has been up for 2 1/2 years. What is the
> argument that favors putting styro under the tanks?

The main one is that, should there be any hard debris or high spots on
the surface where you're placing the tank, you don't have to worry about
that causing the glass to crack. Sure, you check the surface first
and clean it, but why take any chances with something that big and
expensive?

In my experience with the 130g tank, the foam compresses surprisingly
little (< 0.25")

[NetMax]

"Dick" > wrote in message
...
> On Wed, 20 Jul 2005 22:12:48 -0500, "John ><>"
> > wrote:
>
>>> In the bigger picture, perhaps a 20g doesn't really need foam
>>> underneath,
>>> but if you insist, then use a thin sheet (so it doesn't slip off from
>>> compressing the material) and leave a little extra around the edges
>>> (useful for smaller tanks with thinner edges)..
>>> --
>>> www.NetMax.tk
>>
>>I have 1" Blue Styro under my 1000g. It really helps keep the weight on
>>the
>>base even. I have one 120 that is supported Only at the corners, and has
>>been that way for 5 years, the other 120, 75 & 55 are on a flat surface
>>all
>>around w/o foam.
>>
>>JOhn ><>
>>
>
>
> I had never heard of putting styro under tanks when I set up my tanks.
> My 75 gallon tank has 100 lbs of gravel and the base cabinet only
> supports the tank frame. It has been up for 2 1/2 years. What is the
> argument that favors putting styro under the tanks?
>
> I have quit using bio wheels, charcoal and my bubblers. There seem to
> be lots of "beliefs" that "ain't necessarilly true" as the old song
> puts it.
>
> dick



imo..

Bio wheels have a very good functionality. How useful they are to anyone
really depends on their set-up.

Charcoal (activated carbon) also does what it's supposed to do, and its
usefulness again depends on your set-up and your natural water conditions.
Like you, I don't use it as part of my regular filter media. Until I need
it, I try not to spend money on things.

If you have a sturdy stand which is properly flat, and your empty tank sits
flush enough against the stand to prevent a business card from sliding
underneath the corners, then there is no need for any materials like
styrofoam to distribute the pressure. If there is a gap, then the tank (and
stand) will try to flex to fill the gap when it is filled with water. You
need to decide yourself if the amount of flex is acceptable. Neither glass
or silicone will flex very much, possibly still leaving a gap. A small tank
might live problem-free with a gap, but larger tanks (especially cheap tanks
made of thin glass) are less tolerant (and more problematic due to the
volume of water they might release). There is a certain amount of 'sheer'
that silicone will take (holding in the water) and a gap underneath may
cause additional sheer or pull-away force which will test the safety margin
of the tank's construction.

Likewise, if the stand warps, or absorbs the vertical pressure unevenly, it
may create a stress point. This is minimized by styrofoam, but the solution
is to have a proper stand ;~).
--
www.NetMax.tk

[NetMax]

"Nikki Casali" > wrote in message
...
> NetMax wrote:
>
>> "Dick" > wrote in message
>> ...
>>
>>>On Wed, 20 Jul 2005 22:12:48 -0500, "John ><>"
> wrote:
<snip>

>>>I have quit using bio wheels, charcoal and my bubblers. There seem to
>>>be lots of "beliefs" that "ain't necessarilly true" as the old song
>>>puts it.
>>>
>>>dick
>>
>> imo..
>>
>> Bio wheels have a very good functionality. How useful they are to anyone
>> really depends on their set-up.
>>
>> Charcoal (activated carbon) also does what it's supposed to do, and its
>> usefulness again depends on your set-up and your natural water
>> conditions. Like you, I don't use it as part of my regular filter media.
>> Until I need it, I try not to spend money on things.
>>
>> If you have a sturdy stand which is properly flat, and your empty tank
>> sits flush enough against the stand to prevent a business card from
>> sliding underneath the corners, then there is no need for any materials
>> like styrofoam to distribute the pressure. If there is a gap, then the
>> tank (and stand) will try to flex to fill the gap when it is filled with
>> water. You need to decide yourself if the amount of flex is acceptable.
>> Neither glass or silicone will flex very much, possibly still leaving a
>> gap. A small tank might live problem-free with a gap, but larger tanks
>> (especially cheap tanks made of thin glass) are less tolerant (and more
>> problematic due to the volume of water they might release). There is a
>> certain amount of 'sheer' that silicone will take (holding in the water)
>> and a gap underneath may cause additional sheer or pull-away force which
>> will test the safety margin of the tank's construction.
>>
>> Likewise, if the stand warps, or absorbs the vertical pressure unevenly,
>> it may create a stress point. This is minimized by styrofoam, but the
>> solution is to have a proper stand ;~).
>
> I had a veneered chipboard stand that was perfectly flat when I bought it.
> Over 12 months one corner expanded due to condensation dripping down on to
> it from the canopy. I didn't discover this until I found half the tank
> empty and water dripping from the ground floor ceiling. There wasn't a
> polystyrene layer between the tank and base. I wonder whether this could
> have prevented the tank base from cracking?
>
> Nikki

Possibly, but probably not in any real significant way. The exposed wooden
edge would still have gotten wet and expanded. Polystyrene would have
absorbed some difference, so that your leak would have taken longer to occur
(if it were to still occur), so the extra time might have allowed you to
have noticed the problem before it got worse and caused a major leak.

Cover drip from condensation is a problem I often see with airstones (one of
their drawbacks) so ymmv.
--
www.NetMax.tk