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Quick setting concrete with color additive in marine tanks?


AquaticEngineer

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Wanted to get some of your perspectives on the use of quick setting concrete in marine tanks.

 

I'm going to be coating large diameter PVC pipes in quikcrete with a dark color dye additive to make it look like wood.

 

The end goal is to create some light weight, easily stackable, immitation pier pylons for my coldwater marine tank.

 

Has anyone used quick setting concrete with a color additive in their marine tanks before?

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The guys at garf.org have done quite a bit of work with concrete, you may pick up some ideas from them. I liked the idea of adding rock salt to the mix to make a more porous final product after the rock salt dissolves during the curing process. They also cover the curing process in some detail.

 

Brian

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I've seen it used in large tanks, like public aquariums. The only concern is the high presence of silica (silicon dioxide) that could leach into the tank and give you some algae issues. But silica is present in playsand which is used by many aquarists for deep sand beds with success.

To a certain extent, silica is present in what we call "live rock".

The best thing to do would be to cure it in saltwater for a few weeks and then have the water professionally tested

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Try maybe the spray pond foam and paint it with the Krylon Fusion spray paint?

 

I dont know that the pvc will have enough weight to counter the boyency of the foam. But thats something I will definately try out, I have a couple cans of the black pond foam in the garage still.

 

I have been looking into using some kind of resin though, anyone use anything like that before?

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I have made a large amount of concrete rocks (at least several hundred lbs.). It takes about a year of curing to get it so they don't leach alkalinity into the water. Fresh concrete can change the pH of salt water up into the 12 range. That is lethal to most life. :( Once algae and other stuff starts to grow on the rock, the base color becomes irrelevant. So adding color is probably not needed. I agree that adding salt to the mix before setting creates a more porous and less dense rock structure.

 

It sounds like if you do the fiberglass/resin it would be your best bet.

 

dsoz

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Just a thought' date=' what if you cured the concrete and then sealed it with the resin?[/quote']

 

Very Clever!

 

That would solve your leeching issues. I was thinking more in lines of taking lead weight coated with silicon and stick them in the form rock to add weight to them!

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Just a thought' date=' what if you cured the concrete and then sealed it with the resin?[/quote']

If I was going to take the time to cure the concrete I probably wouldn't bother with the resin at that point. But thats a good idea to get the color on it that I want over top of the concrete. But if I was going to use the resin I would just fiberglass the columns to begin with.

 

Very Clever!

 

That would solve your leeching issues. I was thinking more in lines of taking lead weight coated with silicon and stick them in the form rock to add weight to them!

One of the reasons I was tentative to use concrete is the potential for leaching later down the road from concrete that wasn't exposed to water during the curing process that later may become exposed. I think adding lead to the tank in any form is just asking for trouble, especially in a coldwater tank that is more suseptable to metals in the water.

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