Is putting something under rockwork a good idea?

[DerpFish]

I'm curious why it isn't a more common practice to put something under the rockwork in a tank. I know some people will put eggcrate or pvc board under it, but it seems most people just put the rocks directly on the glass.

It is pretty commonly suggested to put a mat between the tank and the stand to minimize pressure points, but why aren't the pressure points from the rocks in the tank often addressed?

I'm currently getting a 150g tank set up and am debating whether I should put something under the aquascape. What is everyone else's opinions on this?

 

[Bucs20fan]

It highly depends on if you want bare bottom or not. If you dont want bare bottom then a couple inches of sand, with the rocks pushed down to the glass is just fine for most of us.

 

[diverjm]

I got a sheet of 3/16” polypropylene and siliconed it down to the bottom glass. I placed my rockwork on top then added sand. It gives me added piece of mind and the sand hides it so it was a win win.

 

[DerpFish]

Is putting something under the rocks purely for aesthetic reasons with bare bottoms, or is it done to help with pressure points. I guess I just don't see how sand would be any different than bare bottoms pressure points wise.

 

[DerpFish]

I got a sheet of 3/16” polypropylene and siliconed it down to the bottom glass. I placed my rockwork on top then added sand. It gives me added piece of mind and the sand hides it so it was a win win.

This is kind of what I'm leaning towards doing. It just seems like it would spread out the pressure better and help prevent possible cracking.

 

[Bucs20fan]

This is kind of what I'm leaning towards doing. It just seems like it would spread out the pressure better and help prevent possible cracking.

Nothing wrong with that, but bottom glass on aquariums is meant to withstand hundreds of pounds of substrate and rockwork on top of it. Just not a sudden impact of hundreds of pounds. Kind of like the egg holding up a brick, it is fine with the constant pressure of the brick, just not dropping a brick on it.

 

[stoney7713]

Tank sitting on a pebble is possibly 500 to 1000 pounds on one point. Rocks in the tank, I doubt your balancing them on a pebble point. They also weigh much less, 50 pounds?

If you want you can take the base rock and knock off pressure points, file it down, or rub it on concrete, works well.

I tried egg crate once before and it's more trouble than it's worth if any tank inhabitants dig, it'll show.

 

[DerpFish]

Nothing wrong with that, but bottom glass on aquariums is meant to withstand hundreds of pounds of substrate and rockwork on top of it. Just not a sudden impact of hundreds of pounds. Kind of like the egg holding up a brick, it is fine with the constant pressure of the brick, just not dropping a brick on it.

That's what I've been reading, but I'm just curious as to why people are typically so adamant about putting a mat under the tank when it seems like the same concept.

 

[Bucs20fan]

Thats to stabilize the tank itself on a stand, and make sure there are not pressure points which lead to broken glass and torn seams. We dont worry about the inside of the glass weight wise so to speak.

 

[DerpFish]

Tank sitting on a pebble is possibly 500 to 1000 pounds on one point. Rocks in the tank, I doubt your balancing them on a pebble point. They also weigh much less, 50 pounds?

If you want you can take the base rock and knock off pressure points, file it down, or rub it on concrete, works well.

I tried egg crate once before and it's more trouble than it's worth if any tank inhabitants dig, it'll show.

That's what I've been hearing about eggcrate so I've definitely ruled that out

I do plan on having about 200lbs of rock in the tank branching off of two or three main structures. I also don't particularly like the idea of flattening out the base rock because I feel like it limits some of the available spaces for burrowing species.

 

[Bucs20fan]

That's what I've been hearing about eggcrate so I've definitely ruled that out

I do plan on having about 200lbs of rock in the tank branching off of two or three main structures. I also don't particularly like the idea of flattening out the base rock because I feel like it limits some of the available spaces for burrowing species.

With two or three inches of sand, your rock will be nice and stable. You should have nothing to worry about.

 

[BZOFIQ]

I've always used egg crate under the rocks. When I was removing my 180 after 6 years there were no dead spots or any other issues noticed because of the egg crate. Going to do the same on the 270 now.

 

[stoney7713]

That's what I've been hearing about eggcrate so I've definitely ruled that out

I do plan on having about 200lbs of rock in the tank branching off of two or three main structures. I also don't particularly like the idea of flattening out the base rock because I feel like it limits some of the available spaces for burrowing species.

You don't have to take it completely flat, just knocking down the high points and spreading the load out.

I actually took smaller pieces of flat rock and glued them to a few pieces of the base rocks to make them sit the way I wanted. In turn it left a lot of room beneath the rock.

I can't find pics right now but thing of them like feet or wedges.

 

[crusso1993]

I'm curious why it isn't a more common practice to put something under the rockwork in a tank. I know some people will put eggcrate or pvc board under it, but it seems most people just put the rocks directly on the glass.

It is pretty commonly suggested to put a mat between the tank and the stand to minimize pressure points, but why aren't the pressure points from the rocks in the tank often addressed?

I'm currently getting a 150g tank set up and am debating whether I should put something under the aquascape. What is everyone else's opinions on this?

I’ve always been fond of placing bodies of ex-bosses under rock work. This usually requires a lot of rock but it’s welcome for additional surface area. However, it does require a large, strong tank with additional bracing in the stand. Oh, don’t forget to reinforce the structure if on a second or third floor.

 

[thatmanMIKEson]

In My build threads I use abs board siliconed to the bottom, the abs is easily found online cut to size and thickness, I use it to protect the glass as well as a place to attach corals easier, and it also promotes coraline algae growth faster than glass.

Thread '120 gallon set up' https://www.reef2reef.com/threads/120-gallon-set-up.799164/

Thread '20gallon long tranformed into a 48gallon cube!' https://www.reef2reef.com/threads/20gallon-long-tranformed-into-a-48gallon-cube.845454/

 

[Eagle_Steve]

I’ve always been fond of placing bodies of ex-bosses under rock work. This usually requires a lot of rock but it’s welcome for additional surface area. However, it does require a large, strong tank with additional bracing in the stand. Oh, don’t forget to reinforce the structure if on a second or third floor.

It also provides a good source of nutrients to get the initial bacteria population growing.

 

[thatmanMIKEson]

It also provides a good source of nutrients to get the initial bacteria population growing.

How is that?

 

[Eagle_Steve]

How is that?

Decay leads to ammonia for the bacteria to start the chain for denitrification. Plus you get a carbon source as well.

 

[JPM San Diego]

I have one bare bottom set up. For that tank I placed a thin sheet of black plastic siliconed to the bottom. It looked better than glass and provides some protection for the bottom glass. However, it was impossible to clean back to pristine black plastic. I learned to "enjoy" its coating of coralline algae and calcified detritus. I agree with the comment, a rock sitting motionless on the bottom is not a risk to the glass; dropping a rock is another issue.
In my other tank I opted for a sand bed. I placed a piece of plexiglass on the bottom to protect against falling rocks, primarily for accidents that could have occurred during setup, not so much for after the sand was placed. One thing that I did not consider. The plexiglass is about 3/16 thick and I cannot clean my glass to the very bottom. I can push back the sand to clean the glass, but the last 3/16 inch has a strip of algae. I am learning to "enjoy" it too.
Another thing I did, for which I am very very pleased and recommend for everyone: Under my rock work (real reef purple rocks) I place white dry rock that was cut in half. (MarcoRocks, medium foundation reef saver dry live rock). The flat side goes down and the rough side faces up supporting my rock structures. I purchased two diamond gobies who have tunneled under all of my small "island" rocks. They move sand constantly. My rock structures would have tumbled down by now. The diamond gobies cannot tunnel under my main rock structures as they are sitting directly on the MarcoRock, which sits directly on the plexiglass. My sand bed was placed around these rocks, not under these rocks.

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[Rtaylor]

That's what I've been reading, but I'm just curious as to why people are typically so adamant about putting a mat under the tank when it seems like the same concept.

It’s primarily to aid in leveling. A tank that isn’t level will create stress points on seams.