# DO NOT USE fast setting concrete for DIY Backgrounds



## nipzie (Nov 24, 2008)

I have just been given some information from someone who professionally installs/builds these and they were supposedly having a problem with silicone seals popping after about 12 months. They sent samples off to a lab and the results showed that the additive that was used to speed set the concrete stayed in the concrete and slowly dissolved the silicone until the tank would leak. Interesting to get this from a professional who spent the time and money to find this out. Just thought i'd let it be known, however I don't know what specifically was the speed-curing additive since there are several, so some might be safe as we know salt speeds curing, but better safe than sorry. 
Has anyone had success/failure with a fast setting concrete? And if so share what brand so that others may steer away from particular types. I enjoy the longer working time that I need to make a good sized batch so I've never used it for a background.


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## ctinsley (Apr 24, 2009)

Hey I think this is a post that is well needed in this section. Im working on a DIY myself and im having second thoughts about the crete i chose. Im using qickcrete mortar mix because I figured it would be smoother than traditional crete. It was but I got it wet about three days after I applied it and it got soft like it almost washed away. Maybe i did something wrong but im not giving up on that stuff yet. It made one great and smooth coat on my background. I mixed it with color and acrylic fortifier so im going to do my homework and see where to go from here.


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## bntbrl (Apr 23, 2009)

I have seen several places that say not to use the fast setting stuff for whatever reason.

When I was making live rock I used oyster shells and portland cement to make my live rock. I ran that tank for years withthe rock in it and had no problems with it. I was going to look and see if anyone had used portland cement for backgrounds. The 'concrete' mixes are generally said to be avoided for whatever reason. I cured my liverock by putting it in the back of the toilet tank (make sure you dont use any blue stuff or bleach or whatever cleaners that go in the back). It puts off quite a bit of PH making stuff as it cures. Vinegar seems to help it knock out some of the bad stuff. I just soaked it in there for a week and added it as it cured.

Out of one bag I got more than enough rock for a 29 gallon, plus hundreds and hundreds of plugs and other odd things I made with it...

I was going to try my hand with some of the grout mixes too as they come in smaller quantities.


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## tommy022060 (May 1, 2008)

CT did you check if the mortar mix is waterproof?


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## becikeja (Oct 14, 2007)

I used quickcrete to make some rocks for my tank. Now going on a year and half, with no issues at all.


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## iceblue (Apr 27, 2004)

bntbrl said:


> When I was making live rock I used oyster shells and portland cement to make my live rock. I ran that tank for years withthe rock in it and had no problems with it. I was going to look and see if anyone had used portland cement for backgrounds.


I used Portland type II cement, sand and Perlite for my background project. http://www.cichlid-forum.com/phpBB/view ... highlight=


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