Barebottom tank bottoms

[ReeferMan]

What do people on here use for the bottom of their barebottom tanks? I am alittle uneasy about putting rock directly on the glass.

[scott711]

some people use starboard

[ReeferMan]

what about most people?

[traveller7]

I have used acrylic sheet in most instances, but have put rock on glass as well.

[xCGx]

I have rock sitting directly on the glass.

[ReeferMan]

Do you all think that 2400gph through a 75g is sufficient for a barebottom tank?

[fab]

What is your concern about rock sitting directly on a glass bottom?

 

fab

[ReeferMan]

i am alittle worried about stacking the rocks and then it falling over and breaking the bottom glass

[trble81]

I think Copps' big tank is pretty darn close to being bare bottom (I only saw like a handful of substrate in one little pile). You might want to ask him.

 

I know that the bottoms should be made with tempered glass, but that means squat when a land slide of 100 lbs of LR comes crashing down.

[dbartco]

What size tank? I have 2 black 1/2" thick peices of plastic about 17x20. The used to be doors on a peice of vc equip. I used 2 in my 125, cut out the overflow areas and used. hase a slight crack in the middle, but no really noticable.

 

Starbosrd like cutting board material. This is similar.

[fab]

What is the difference between a landslide tumbling down directly onto the glass versus onto a piece of plastic that is lying flat on the glass? The total force of the rocks falling will be transmitted to the glass bottom in either case. I doubt the presence of a plastic sheet will reduce the forces felt by the glass enough to matter. I suppose you could argue that some kind of sandwich or egg crate material might abosrb some of the energy in stopping the fall so that it does not transmit into the glass bottom. I rather doubt, though, that the energy absorption would amount to much, percentage-wise.

 

fab

[YBeNormal]

Sharp points on rocks focus the energy in a very small area and can break the glass quite easily, similar to the safety devices designed to break car windows in emergency situations.

[DaveS]

What is the difference between a landslide tumbling down directly onto the glass versus onto a piece of plastic that is lying flat on the glass? The total force of the rocks falling will be transmitted to the glass bottom in either case. I doubt the presence of a plastic sheet will reduce the forces felt by the glass enough to matter. I suppose you could argue that some kind of sandwich or egg crate material might abosrb some of the energy in stopping the fall so that it does not transmit into the glass bottom. I rather doubt, though, that the energy absorption would amount to much, percentage-wise.

 

fab

 

It's not about total force, it's about force over area (PSI). Since rocks are not uniform shape and often times have pointy parts, that's the real problem. If a rock falls on the glass, pointy part first, you are essentially exposing your glass to a force much higher amount of force over that area if it hit on a flat part. I could use specific numbers but I'm sure you get the idea.

 

By having a sheet of something between the rock and the glass (as long as it doesn't shatter easily) you are essentially spreading that pointy impact over the entire (or at least some larger area) portion of the glass. This should help reduce the likelihood of the glass breaking.

 

It's the same principle as why sitting on a chair with a seat is much more comfortable than sitting on the side of a 2x4. You don't weigh more in either case but with a seat, your weight is spread more across your butt....