# Does this work? DIY aquarium decor/backgrounds using styrofoam and quickcrete?



## PlantedRich (Jul 21, 2010)

This is an area where it seems to work but when I look at it further, I find many problems that keep it from being a project for me. 
My view just for info?
One stopper for me is that it IS permanent. Any major design mistake is very difficult to change. It all can be made to work but it has lots of ways to get it wrong and some can be a major problem. One is getting it designed to avoid whatever is holding it down to stay. If it comes loose and not designed to stay down, it can come loose suddenly and shoot to the top. I read about losing glass tops and lights as the "sub" comes up!
Filtering and water flow behind and under the background has to be designed to avoid dead spots where water becomes stagnant. Lots of flow has to then have ways to keep fish and debris from collecting under and behind. Quickcrete is very alkaline. How to soak it, treat it, or deal with the way it may change your water? 

All these can be dealt with but for me, I don't need the hassle. For African cichlid tanks, I was tempted but then flat limestone rocks are much cheaper and far easier to deal with in my area. They also look like rocks, which mine do not! I have a cheap ($50) tile saw which makes it easy to cut and fit rocks to make the background. I find it much easier to design as mistakes can be corrected, it doesn't float and can be taken apart and sections changed if I'm not right the first time. For caves and things that might have to move, I don't want them permanently attached or sealed so that they become stagnant. 
Works for some but it is not for me.


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## Ltraine (Apr 30, 2014)

Thank for the advice , i was having the same doubt about this project regarding the bouyancy and alkalinity of the fixtures. the good news is time isn't necessarily a scarcity for this project because 1)I'm broke so i'll have to piece it together little by little and 2) i want to do this right so i don't mind taking longer to even just get the hardscape down if it means i get something really cool and unique in the end.

i'm not really opposed to having to soak peices for a while to allow for leeching to occur, however i'm fairly inexperienced in this matter (i've always used store-bought decos or rocks that i boiled)

what about using this method to create only some of the aspects of the hardscape not the entire background like it is in the link? maybe make it hollow on the inside and leave holes for it to fill up with water or sand or something? i got this tank for $25 at a yard sale so i'm not opposed to making the hardscape semi permanent by gluing things to the bottom with silicone but if i can avoid it i will


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## jeffkrol (Jun 5, 2013)

PlantedRich said:


> Quickcrete is very alkaline. How to soak it, treat it, or deal with the way it may change your water?
> 
> All these can be dealt with but for me, I don't need the hassle. For African cichlid tanks, I was tempted but then flat limestone rocks are much cheaper and far easier to deal with in my area.


considering your Cichlid tank neither seems to be too problematic (YMMV).. both can harden the water.. sometimes.. under some conditions.. 
http://www.cichlid-forum.com/articles/rock_metals.php


> And not all limestone is equal..
> 
> This means that if you have a tank running at pH 7 with any of the myriad fish that are happy at a near neutral pH such as tetras, corys, many South American cichlids, kribs, gouramis, rasboras, danios, etc etc. then carbonate rocks are not an automatic no-no, as is often suggested. In most cases, such rocks may cause the pH to drift up a few decimal points but it will normally remain within the acceptable range for such fish. You can easily check this by putting such rocks in your tank and testing the pH at weekly intervals. If you find it is moving up steadily and reaching undesirable levels for the species, just remove it. It will not have harmed your fish in the meantime.
> On the other hand, if you run a tank with acidic soft-water conditions at pH 6.5 or below for certain species, then you clearly do not want to introduce anything that will tend to move the pH or hardness upwards. In such cases all carbonate rocks should be strictly avoided.


Remember just guidelines, but yes permanent concrete sure could be a problem IF it becomes a problem..


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## vanish (Apr 21, 2014)

You don't have to use concrete at all, skipping that whole leeching phase and ph issues. I sealed the foam with Drylok directly. I did one un-pigmented, thick "primer" coat of straight white Drylok. Then another layer of thick, dark-colored. After that it was various detail coats.

The background cost me about $35 in materials, most of which was spent on the Drylock and tinting. Its 48 in. x 20in., but I only needed 1/4 to 1/3 of a gallon of Drylock to do all my coats. I barely used any tint coloring at all. I have enough materials to do several more backgrounds for other tanks.

Its absolutely true though that you better like what you made, because its not easy to change it one it is silicone'd in! Everyone that has seen my DIY background in person has loved it. Are there some things I wish I would have done differently? Of course, but I am definitely glad I did it.

$2 - 1 sheet of 2 inch thick blue foam, purchased at Habitat ReStore (you might be able to get some free at a local furniture store
$4 x 2 - Concrete Tint
$22 - White drylok
$5 - Silicone


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## kdv9tb (Oct 28, 2011)

+1
I also have used the dryloc and stryofoam method. I really like the outcome, and it has been submersed for 2+ years now, with no issues. I did make mine removeable, so it didnt void the warranty. I attached suction cups on the back of the tank for this.

Another option I have seen done, is to go to the paint section of a hardware store (Lowes for me), and bondo makes a waterproof epoxy kit. Sells for like $15-20. I have seen many people use this for the saltwater tanks, but I personally have not tried it. You then can just "paint" whatever cave, rock wall, or decor you choose.


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## Ltraine (Apr 30, 2014)

that sounds like a great plan with the drylok. and like i said, i can always hollow out the center and fill it with sand or something to increase mass so buoyancy isn't a huge problem. As an engineering student i feel like i should at least be able to do those calculations haha. what about creating rocks from a sand mold filled with some media and a bonding agent? like in this link here:

http://www.diyaquarist.com/archives/3418

i'm sure the above method would work in marine aquariums but what about freshwater? sorry for all the questions i just wanna make sure i dont wate time/money building something that is going to be toxic to my fish.


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## wheatiesl337 (Mar 30, 2011)

You may be interested in checking out my journal. I made a background in a 55g using expanding foam and dyed cement. I am quite happy with the results. I would be happy to answer any specific questions.


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## GraphicGr8s (Apr 4, 2011)

Take a look here

http://dramaticaquascapes.com/


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## lochaber (Jan 23, 2012)

I've made a couple paludariums using styrofoam coated in a sand/epoxy mix. 

The ones I made were glued in, so they would be really difficult to remove, but I'm toying with the idea of getting a big enough block of stryofoam that I can effectively wedge it in the tank, with just a couple dots of silicone to secure it/seal the edges. That way I think I should be able to pull it out (breaking the stryofoam around the silicone), and then just scrape off a couple silicone blobs. Haven't tried it though, so there are probably all sorts of unforeseen problems.

Also, if you do decide to remove it, you could try setting the tank on it's back, and using some solvent that dissolves stryofoam, pour that down the edges, etc. You'd just have to make sure it's not something that will affect the silicone, and keep it away from the rim.

Anyways, I really liked the results of a sand-epoxy mix. Real easy to use, gave a nice hard, rough, rock-like surface, and it was heavy enough to hold the styrofoam down (this depends a lot on your design, and volume-surface area ratios, etc.). If you used a more viscous epoxy resin, you could probably end up with a fairly mold-able sand/epoxy mix, and directly form your shapes that way.


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## Ltraine (Apr 30, 2014)

thanks everyone for all the input, i definitely have alot of options to go with now. i have changed my design plans a little since i first posted this thread, but even so, this is all very helpful.


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