JC Pollman
Premium Member
I have considered using the foam, but with the rock work sitting on it, I doubt it will be strong enough, and there is the added expense of covering it with epoxy - 16 sq feet is alot of area to cover.
The Ultimate DIY Rocks!
- Thread starter JohnL
- Start date
Rhodophyta
New member
In my pond I have a three foot tall rock waterfall sitting on it. These are normal (heavy) rocks, not the lightweight porous rockwork for a marine tank.
It is made to be submerged. Who told you to cover it with epoxy? A clerk at a chain pet shop? The nice thing about the waterfall foam is it's one step. Spray it and as soon as it's dry, use it.
JC Pollman
Premium Member
You are talking about the black pond foam? If so, this sounds like a much better way to go - if nothing else, it will be much easier when it eventually (like in 25 years) needs to be taken down.
Doing some quick research on covering with epoxy:
"Foam which is exposed to direct sunlight should be painted to protect against gradual decomposition."
from: http://www.watergarden.org/s.nl/id.13/.f
Doing some quick research on covering with epoxy:
"Foam which is exposed to direct sunlight should be painted to protect against gradual decomposition."
from: http://www.watergarden.org/s.nl/id.13/.f
Rhodophyta
New member
There is not going to be direct sunlight in your tank is there? Even in my pond waterfall where some of the foam is out of the water (which is a lot of protection) and has been in direct sunlight summers and winters for years, that foam is still fine too.
I remember one of the MACNA talks comparing our lighting systems' lumens to that of the sun's over tropical reefs. Ours is only a tiny fraction of real sunlight, and has even less percentage of the damaging UV wave lengths.
Re: cement on the bottom of the tank?
Re: cement on the bottom of the tank?
i posed the same question a while back. Be sure to check out the link in the first post.
this thread
Re: cement on the bottom of the tank?
i posed the same question a while back. Be sure to check out the link in the first post.
this thread
eznet2u
Active member
Well I made a few OS rocks and am very pleased with the results... really as porous as it can be and looks great !
But now, I let them in a warm place for over a month to cure and I am now in the kuring process... the rocks have been in the water for close to 3 weeks now, and they still "release" a fair bit of "white powder" in the water. It forms a film on the water surface and will eventually become thick enough to form a "thin crust" (if I don't do a water change before). As I know they are not ready yet, I have not bothered with PH mesurements so far.
First time I use OS and white cement (3:1) so I would like to know if that "white powder" is normal at this point and if it will completely go away as the rocks mature... ???
I am using 2 power heads and one heater in the tank (water is kept at 82-84 F)
Thanks for your help !
But now, I let them in a warm place for over a month to cure and I am now in the kuring process... the rocks have been in the water for close to 3 weeks now, and they still "release" a fair bit of "white powder" in the water. It forms a film on the water surface and will eventually become thick enough to form a "thin crust" (if I don't do a water change before). As I know they are not ready yet, I have not bothered with PH mesurements so far.
First time I use OS and white cement (3:1) so I would like to know if that "white powder" is normal at this point and if it will completely go away as the rocks mature... ???
I am using 2 power heads and one heater in the tank (water is kept at 82-84 F)
Thanks for your help !
Rhodophyta
New member
I think that the white powder (efflorescence) is often because the rock was submerged way too early but it has many causes. If the rock has time to chemically bond, submerging will not have as much to leach away. Concrete Technology has a simple way to avoid efflorescence, keep the concrete relatively dry. No help there to us, except right at the beginning before we begin to bio-condition the rock.
Thanks Rhodo.
But the rocks have been dry (meaning kept moist in a plastic bag in a warm place) for 4-6 weeks before I submerged them ! I thought that would be long enough...
Also, I am not sure (and here just guessing!) if the white stuff come from the cement or from the oyster shells ??? But as I said, first time I use white cement and first time I use OS also !! My only experience is with a complete DIY background made from mason mix, and it barely shed any powder in the water...
But the rocks have been dry (meaning kept moist in a plastic bag in a warm place) for 4-6 weeks before I submerged them ! I thought that would be long enough...
Also, I am not sure (and here just guessing!) if the white stuff come from the cement or from the oyster shells ??? But as I said, first time I use white cement and first time I use OS also !! My only experience is with a complete DIY background made from mason mix, and it barely shed any powder in the water...
Rhodophyta
New member
Crushed oyster shell will definitely produce a white powder, but it usually 90% goes away after a water change and the residue gradually is used up by tank life that needs calcium. The shell is often a byproduct of oyster harvesting and may have bits of mangrove root and other contaminants. I found it best to wash it before use, using a "flood" of water that would lift off the floaters such as ground up wood and the "foamy" part of the oyster shell.
Rhodophyta
New member
What we need to do is find out what the witch in the Wizard of Oz was made of.
Rhodophyta
New member
Actually, it might be a good idea. You could re-use the wax and parafin wax is inert and fairly cheap for a petrolium product. You could also weigh it before and after so you would know if there was any still trapped in the rock.
customcolor
New member
how would the wax get out from inside the rock? i know water can get in there to get out the salt put it takes weeks. you might beable to ues chunks of wax for the molding part of making the rock but i dont think i would used it for in side the rock.
With the kind of rock I made, there is no way that wax could come out of there !
But if you use a really dry mix and don't "push it in the mold", I don't see why you have to use salt... I mean my rocks are really very, very porous and I just use wet sand for casting...
OK, so for the white powder, even if there is still some left, if my PH goes down, that shouldn't be a problem in my tank... right ?
But if you use a really dry mix and don't "push it in the mold", I don't see why you have to use salt... I mean my rocks are really very, very porous and I just use wet sand for casting...
OK, so for the white powder, even if there is still some left, if my PH goes down, that shouldn't be a problem in my tank... right ?
