Fill PVC anchors for aquascape with sand or water in 6" sandbed?

[spd3001]

I'm building out a 90 gallon reef tank with a deep sandbed. The tank is 36" deep and 24" square. I plan on keeping a yellow-headed jawfish and likely a goby/shrimp pair. They'll be digging up the sand so I want to anchor my aquascape to a PVC skeleton that will be buried beneath the sand. I don't want them to be able to shift the aquascape around. So what should I do, fill the pipes with sand or just leave them open and let them fill as they may? Should they be water-tight and empty and epoxied to the bottom of the tank? Anybody have some related experience they can share? The bed will vary in depth from 5 to 8 inches.

 

[Saltyreef]

Put the rock down first then fill in with sand. Unless you have flat base pieces the gobies and shrimp should be happy.

 

[spd3001]

Put the rock down first then fill in with sand. Unless you have flat base pieces the gobies and shrimp should be happy.

I'm not comfortable about just burying it. I'm using branch rock that really does need to be secured. I don't want it to shift and injure animals or scratch the glass. The tank is only 2' x 2' (but 36" deep) and I need to keep it off the sides so I can keep them clean as well. So the question remains, fill the PVC with water or sand or seal them shut with nothing but air (the rock and sand will handle any buoyancy.)

 

[Saltyreef]

If you arent sealing them water tight on both sides, they will naturally fill with water and this will suffice to create an equalibrium with the weight of the rock. Pvc pipe doesnt foat anyways.

 

[theMeat]

If you arent sealing them water tight on both sides, they will naturally fill with water and this will suffice to create an equalibrium with the weight of the rock. Pvc pipe doesnt foat anyways.

Pvc pipe floats. Pvc fittings do not

 

[sp1187]

Pvc pipe floats. Pvc fittings do not

strange, my pvc pipe "rollers" I use to move my boat across a dike don't float.

 

[sp1187]

Habitat Black from Smooth On is a two part putty that dries hard like concrete.
binds to pvc. my whole scape is pvc and this two part.
so you could use it to permanently attach your scape to it.

 

[theMeat]

strange, my pvc pipe "rollers" I use to move my boat across a dike don't float.

What diameter?
Cell core or solid ?
Saltwater or fresh water?
Since op is putting rocks on it, it doesn’t matter.

 

[Viridis]

Pvc pipe floats. Pvc fittings do not

I use PVC pipe as hides in fish tanks all the time... always sinks.
ABS does float though.

 

[sp1187]

What diameter?
Cell core or solid ?
Saltwater or fresh water?
Since op is putting rocks on it, it doesn’t matter.

Sched40
diameter doesn't matter.
fresh or salt doesn't matter.
it doesn't displace enough to overcome it's weight.
it sinks.

 

[Saltyreef]

Pvc pipe floats. Pvc fittings do not

Really? Looks like my pipe must have an iron core.....
Ill call the hardware store in the morning to complain!

 

[jaxteller007]

Man nori sheets must be heavy if they sink my pieces of pvc pipe to the bottom of the tank.

 

[theMeat]

Schedule 40 fitting are always, as far as I know, solid pvc and do not float.
Schedule 40 pipe may be cell core or solid core and cell core floats. Forget the exact formula but bigger pipes float more than smaller pipes.
I see you guys were having fun with making fun of me but unfortunately I had nothing better to do.
Here is a pic of smaller pipes (solid core) that sank. A 3” cell core that floats, and a 3” solid core that sank, and a 4” cell that floats. I’d bet you money you couldn’t tell the dif between cell and solid by looking at em unless you picked up two same sized pieces at the same time and felt the difference. As well, this is in fresh water. Saltwater is heavier and more dense than fresh so things are more buoyant in it. You know dense, right...

 

[theMeat]

Man. Thought this place was about floating and sharing info and knowledge. Not piling on and sinking fellow members like you did in junior high school popularity contest

 

[Saltyreef]

Man. Thought this place was about floating and sharing info and knowledge. Not piling on and sinking fellow members like you did in junior high school popularity contest

You should have been more specific in your first comment of "pvc pipe doesnt float" because its not true.
Just correcting false info.
If you had given your example of solid core and cell core first we could have understood more of what you "actually meant".

 

[sp1187]

Schedule 40 fitting are always, as far as I know, solid pvc and do not float.
Schedule 40 pipe may be cell core or solid core and cell core floats. Forget the exact formula but bigger pipes float more than smaller pipes.
I see you guys were having fun with making fun of me but unfortunately I had nothing better to do.
Here is a pic of smaller pipes (solid core) that sank. A 3” cell core that floats, and a 3” solid core that sank, and a 4” cell that floats. I’d bet you money you couldn’t tell the dif between cell and solid by looking at em unless you picked up two same sized pieces at the same time and felt the difference. As well, this is in fresh water. Saltwater is heavier and more dense than fresh so things are more buoyant in it. You know dense, right...

see... it does sink.

 

[theMeat]

see... it does sink.

Unless it floats

 

[ca1ore]

Now that one of the great mysteries of the universe has been solved, back to our regular programming.

I used a pvc frame to hold up a rock pedestal. 1” bulkhead through a 8” by 8” piece of acrylic. 1” black pvc pipe into the bulkhead. Drilled a few holes in the PVC to prevent stagnation. I siliconed the acrylic square to the tank bottom because I only have 2-3” of sand, but under 6” of sand I doubt silicone is necessary.

 

[theMeat]

You should have been more specific in your first comment of "pvc pipe doesnt float" because its not true.
Just correcting false info.
If you had given your example of solid core and cell core first we could have understood more of what you "actually meant".

Not true? Whatever. Op wanted to know if pvc pipe floats. Since it’s hard to tell the difference between cell or solid by looking at it I took the safe route without getting into the whole thing. Also said it doesn’t matter since rock is going on top of it.

 

[theMeat]

Let’s not get into how much tin will be introduced into water with a bunch of added pvc structure