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.

 

[spd3001]

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.

Thanks! I guess what my concern is that the inside of the PVC would go anaerobic and let something deadly grow that could easily travel up out of the anaerobic levels of my deep sand bed. What could prevent that from happening. Is it even a likely scenario? If the pipe was packed with sand, it seems the anaerobic stuff would stay where it was since nothing would be disturbing it. Maybe I'm just letting my imagination run away from me.

 

[krash7172]

Valid question. Just don't seal with air in it and you will be fine.

 

[ca1ore]

Thanks! I guess what my concern is that the inside of the PVC would go anaerobic and let something deadly grow that could easily travel up out of the anaerobic levels of my deep sand bed. What could prevent that from happening. Is it even a likely scenario? If the pipe was packed with sand, it seems the anaerobic stuff would stay where it was since nothing would be disturbing it. Maybe I'm just letting my imagination run away from me.

First of all it's going to be a very small amount of volume, so I would not overly worry about it frankly. Second, to err on the side of caution, that is why I drilled a bunch of holes in the pipe. Big enough to provide ingress and egress for bristle worms.

 

[Saltyreef]

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.

You're right. I should have said your comment was "partially correct".
I apologize.

 

[theMeat]

You're right. I should have said your comment was "partially correct".
I apologize.

You’re right too. I could have been clearer.
Shwoo, glad that’s over. Maybe we all learned something

 

[Saltyreef]

You’re right too. I could have been clearer.
Shwoo, glad that’s over. Maybe we all learned something

I also learned foam or cell core pvc is not something commonly found at your hardware store and will only be sold for DWV purposes like black ABS DWV pipe as it is not meant to be pressurized.
So likely, he wont be running into this specialty pipe unless hes ordering it from a plumbing supplier.

Any pvc he gets will sink as its 99.9% likely NOT to be cell core DWV pvc

 

[ca1ore]

A few years ago I bought some 6" pipe for QT shelter and was shocked to see that it floated. Figured that the laws of physics had suddenly shifted so took all my investment assets and bought a three large feed corn silos (including the corn). Gotta eat as the world ends right! Wish I'd known then about cell core PVC. Large corn silos aren't easy to resell apparently.

 

[theMeat]

I also learned foam or cell core pvc is not something commonly found at your hardware store and will only be sold for DWV purposes like black ABS DWV pipe as it is not meant to be pressurized.
So likely, he wont be running into this specialty pipe unless hes ordering it from a plumbing supplier.

Any pvc he gets will sink as its 99.9% likely NOT to be cell core DWV pvc

For the last 10 years or more it’s 4” or bigger it’s likely cell core. You’d be hard pressed to find any solid at homecheapo and the likes. In the last few years it’s creeping down to 3”.

 

[Saltyreef]

For the last 10 years or more it’s 4” or bigger it’s likely cell core. You’d be hard pressed to find any solid at homecheapo and the likes. In the last few years it’s creeping down to 3”.

Again...cell core has a designation and its for drain, waste, vent.

Size isnt the determining factor here...

I can find 1.5" cell core dwv pipe online.

 

[Dkmoo]

Not sure if its too late for you but I used acrylic "stilts" glued to a sheet and put that in first before sand. Here's an extra piece i later pulled out of the tank.

 

[theMeat]

Again...cell core has a designation and its for drain, waste, vent.

By that logic all pvc down to about 1” should be, could be, cell core for residential. Vertically no houses have bigger than 1” supply.

 

[theMeat]

Again...cell core has a designation and its for drain, waste, vent.

Size isnt the determining factor here...

I can find 1.5" cell core dwv pipe online.

I see you added, edited.
If you can’t find 1.5 cell core pvc you’re not looking hard enough, and if you’d like to keep argue with a plumber of 30 years for no reason, please...

 

[Saltyreef]

By that logic all pvc down to about 1” should be, could be, cell core for residential. Vertically no houses have bigger than 1” supply.

Most of the pvc sold at home steepo or lowes is geared towards irrigation anyways. 2" pressure rated pvc down to 1/2" usually.
DWV stuff is black ABS.
They may carry cell core but again, it would say DWV and "not for use in pressurized systems"

 

[Saltyreef]

I see you added, edited.
If you can’t find 1.5 cell core pvc you’re not looking hard enough, and if you’d like to keep argue with a plumber of 30 years for no reason, please...

I added the . Between 1 and 5 lol....

And i did. It was an easy google. Still for DWV.

Show me where in your 30 years of plumbing experience its acceptable to use cell core DWV only pipe in a pressurized application.....
And ill shut up lol.

 

[Saltyreef]

Just sayin OP likely wont be dealing with cell core pvc. All he has to do is look at the inking on the pipe.....if its white pvc and says DWV....it likely will float!
But....he likely wont run into any.

Edit: reg sch 40 pvc is dual marketed as DWV.
If it has a pressure rating its 99.99% not cell cast. Dont go based off the DWV application as i said before.

 

[garbled]

I have a PVC structure for some rocks in my reef. I drilled a bunch of holes in them so they wouldn't capture air, and could have a tiny bit of water movement. I figured like every 6-12" a 1/4" hole was good. The rocks sit on them and hold them down, though they did hold by themselves ok. Basically I put them in first, then put in sand around them, then put rocks on them.

I have had no problems with this setup.

 

[terraincognita]

FWIW, I have a jaw fish and a goby pistol pair.

It's almost like their know where NOT to dig.... if that makes any sense....

I recently had to move my tank which was a slight disaster, but since they've remade all their tunnels and my entire scape is sitting on top of my sand now where priorly it was on the glass.

No issues at all. I wouldn't worry TOO much about it crushing them.

On the reverse my last pistol shrimp died when I had an earthquake and it made my entire scape fall.... soo... maybe you should worry dunno where you live.

 

[theMeat]

Most of the pvc sold at home steepo or lowes is geared towards irrigation anyways. 2" pressure rated pvc down to 1/2" usually.
DWV stuff is black ABS.
They may carry cell core but again, it would say DWV and "not for use in pressurized systems"

Boy. You + google = expert.
I’ll leave you to it.

 

[Saltyreef]

Boy. You with google = expert.
I’ll leave you to it

Me with the lowes down the street and 1.5" sch 40 solid pvc in my garage that i just verified the nomenclature on

Didnt need google for that.
Google only told me multiple times that cell cast sch 40 pvc is DWV only. Solid sch 40 pvc is dual marketed as DWV and for use in pressurized systems.

Common sense from my trade as a building engineer knows DWV only pipe is not to be pressurized.
But what do i know, i havent been plumbing for 30 years.

 

[spd3001]

FWIW, I have a jaw fish and a goby pistol pair.

It's almost like their know where NOT to dig.... if that makes any sense....

I recently had to move my tank which was a slight disaster, but since they've remade all their tunnels and my entire scape is sitting on top of my sand now where priorly it was on the glass.

No issues at all. I wouldn't worry TOO much about it crushing them.

On the reverse my last pistol shrimp died when I had an earthquake and it made my entire scape fall.... soo... maybe you should worry dunno where you live.

Thanks for the info. The jawfish is likely to be the first fish in the new build followed by the goby/shrimp pair. Do your's get along well?