Reef safe cement/concrete?

[MatteZ]

So I want to make a frag rack out of cement/concrete. Any suggestions on what is safe to use? I was thinking of making half moon shape rock type idea. Something that I can stick on the sand bed in the front of the tank that I can drill a bunch of plug holes and put a bunch of spas or something that needs low light low flow. I don't want something that protrudes high into the air.

 

[mrehfeld]

i've researched this a while back and my understanding is that white Portland cement is used with aggregate and sand to make the rocks which must be rinsed over a number of months until the PH stabilizes. It's common for people to use the 3-2-1 ratio when mixing the dry components.

 

[MatteZ]

I was hoping it would be something easy and quick to do. I remember seeing awhile back about where you couple buy something like it but now I can't seem to find it.

 

[JasonB]

I would think you might want to consider using something like food safe plastic. I know it may not provide the look you are going for, but will be safe and functional.

 

[Jing_xoxo]

I went to home depot cause ibwas making a diy coral viewer and I bought this reef safe putty thing its like silicon but not. Its a sealant and I bugged a guy to help me find it. It was 5$ and in a decent size tube im sure you could make plenty of frags plugs with it.

 

[dnov99]

How about one of the frag stations from alternative reef?? I think these go for $20-$25.

 

[MatteZ]

How about one of the frag stations from alternative reef?? I think these go for $20-$25.

That's the one I was looking for! You da man Darren!

 

[dnov99]

That's the one I was looking for! You da man Darren!

I am actually placing an order with him soon for more frag discs. Not to hijack but of anybody needs anything let me know. Matt, do you want me to order one of these for you?? he makes them larger also. They also have them up at the Elos store, but I am not there any longer, so I wouldn,t be able to pick one up for you.

 

[MatteZ]

I think I do want you to order me 1 or 2 of these. can you pm the price and the dimensions of the 3 different sizes please.

 

[Paul B]

I have been building hollow rocks for decades using Sakrete over PVC like this piece.


They start out like this

 

[MatteZ]

That looks awesome! I don't want something that sticks up in the air. I wanted something that I can put on the sand bed and not take up free swimming space. what do you cover the melted pvc with?

 

[Paul B]

You can make any shape you like, I cover the PVC with string like a bakery uses and smear cement on that. It usually takes about 4 or 5 coats as not much will stick the first time.
This piece is cement with real rocks cemented together. It is almost 18" long and is the backbone of my reef.


This one is 3' long and snakes over my reef.


You can see it here above the Moorish Idol.


This piece, shown before and after, is not seen in my tank as it is used to raise my rock off the bottom.

 

[Zippy69]

That is really cool Paul!

 

[JasonB]

Marine Aquarium MacGyver! They look great and I can imagine if you have a large area to fill would save you a tremendous amount of money. Do you have to soak it to leach out any chemicals before using it for long?

 

[kschweer]

i've researched this a while back and my understanding is that white Portland cement is used with aggregate and sand to make the rocks which must be rinsed over a number of months until the PH stabilizes. It's common for people to use the 3-2-1 ratio when mixing the dry components.

I have seen guys do this in the past for making plugs and discs successfully. Pretty cool trick I saw was to take the plugs they had made put them in a mesh bag and then inside the top tank of the toilet. Every time you flush they are rinsed and water is changed. I forget exactly how long they left then in there but I believe it was 2-3 weeks.

 

[TheJuanAndOnly235]

You can make any shape you like, I cover the PVC with string like a bakery uses and smear cement on that. It usually takes about 4 or 5 coats as not much will stick the first time.

I just may have to do this

 

[Paul B]

I soak them in fresh water for a couple of weeks then throw them in my tank. Probably a third of my tank is now hollow, cement rocks. I would imagine the fact that they are hollow benefits in regard to bacterial growth but I can't swear to it.
I just like the rocks I build better than what I collected. I originally collected all my rock in the sea.
Some pieces like this one has a depression to hold a coral.

 

[Zippy69]

Paul, is the cement you use a mortar mix, grout or what?

 

[Paul B]

either Sakrete Mortor mix of cement mix. The Mortor mix is easier to work with because it is stickier

 

[redfishbluefish]

We had someone I can't remember do a demo at one of our monthly meetings....actually on using cement to attach rock. (Hopefully Ed will chime in because I believe he tried this himself.) He used a hydraulic cement. You can pick this stuff up in tubs that look like about a gallon or two....for 10-15 bucks. One note of caution, this stuff sets up within minutes. So have everything ready to go before mixing with water.



EDIT TO ADD:

I found the old post....it was Merv....who hasn't been on in years.

And he use a cement called thorite.....which I think is now sold under the WaterPlug name.