[rchickering]

Here are some pics of my background that I made of styrofoam and SikaTop.

I purchased a 4' x 8' piece of 2" thick styrofoam from home improvement store for about $30.

This was cut into three pieces that fit the dimensions of my tank and secured together with 100% silicone to make a 6" thick piece.

After a week or so I started carving using a drywall saw/knife. Between the 'rocks' of the background, there are passage ways that fish can swim in/hide/claim as territory.

If anyone has any question, please let me know!

During construction:

Applying SikaTop and additional applications with color added to SikaTop mix:

I purchased the SikaTop from a local construction business. Here is the website to find a dealer near you: SikaTop Distributors

Here are a few final project pics:

I used 100% silicone to attach the background to the tank.

 

[remarkosmoc]

That looks awesome!!! I don't see th passageways you are referring to, can you close up one of them?

 

[Pfish]

Looks great.

Do have a couple questions. On the fourth photo, the one with the brush on the bottom, what did you use to paint the dark areas to make it look like natural rocks, and then later add the reddish hue?

 

[css virginia]

That looks good..I like how you made it. Would certainly add a natural look to a tank. 8)

 

[greenbirds]

Nicely done. One of the better styro-based rock walls I've seen here.

 

[rchickering]

That looks awesome!!! I don't see the passageways you are referring to, can you close up one of them?

Here are a few pics that try to show the passageways. Basically, I hollowed out a little between the rocks. I would guess a papertowel roll, or maybe a little bigger, would fit.

 

[rchickering]

Do have a couple questions. On the fourth photo, the one with the brush on the bottom, what did you use to paint the dark areas to make it look like natural rocks, and then later add the reddish hue?

I mixed the SikaTop with concrete coloring (charcoal) to paint the areas inbetween the rocks and apply the first coat of color.

On the other applications, I mixed the SikaTop with buff, red, red & brown, brown and then applied a layer of dark gray and light gray.

I used a very cheap 1" paintbrush and would 'dab' it on.

The concrete color can be purchased at most home improvement stores. For the colors, I would mix about 1 or 2 cups of SikaTop and then add approx 1 tsp at a time of cement coloring until it was the right shade.

 

[rchickering]

Thank you for all the comments so far!

SikaTop was a bit expensive to buy ($60 for the bag and 1 gallon liquid) but it was much easier to apply than concrete and didn't require any curing time.

I ended up using approx 1/3 of each for this project, which was for my 110 gallon tank.

That leaves some leftover to make one for my 225 gallon tank

 

[D-007]

Very impressive looking background.

As I've never heard of this product, thank you for providing an alternative to using concrete. $60 is worth the price seeing as it cuts down the time before fish can be added. :thumb:

Regards,
D

 

[SoonerCichlid]

So does this product raise the ph in the tank? How long before you put in your fish and how long have they been in it? Because if you don't have to wait for the ph to go down, then why aren't other people using this product. Do you know about the longevity and durablility yet? I agree with the other comments and would rather pay the difference between this product and quickcrete than wait for weeks. It just seems to good to be true! I hope not.

 

[rchickering]

I would guess it would raise the pH some as it is a "cementitious" product.

The background was added to my tank less than a week after adding the final coats of color. There were no issues of colors 'bleeding' into the water. After a few days of drying, I siliconed it to the back of the tank and waited a couple of days for the silicone to set up. I added a light grid (used for lights in drop ceilings) in the bottom of the tank to help distribute the weight of the larger rocks and also siliconed plants down to the grid and added the round bubblemaker.

I then added the large round rocks, the mixture of gravel and aragonite, and filled it with water.

I waited approx 2 weeks after filling my tank before I added any fish (I was out of town for the first 10 days). The substrate that I used is regular black gravel and aragonite. Before adding fish, I tested the pH and it was in the high 7's at that time - which was probably affected in part due to the aragonite.

It has been about 5 weeks since I added fish and I haven't lost any. The website I found that used this is: http://ice1forum.suddenlaunch3.com/inde ... 1115002332

Here is a picture of his project - he did more of a big rock with cracks instead of individual rocks. I wanted to use some rounded rocks in my tank and thought it wouldn't fit in well with the 'jagged' look he did - although his does look really good!

I e-mailed him and he said his is still going strong after 3 years and his fish are doing fine.

For some reason I couldn't download the pdf files on Sika's website to share more product specs. I remember that it was approved for use in drinking water systems.

Here is a link to a youtube video (it is in Spanish, but there are a lot of pictures to show what you can use it for!):

I did a test run with regular concrete for a 20 gallon I have and using the SikaTop was MUCH easier. The SikaTop is a 'slurry' so you mix it fairly runny and it can be painted on. They do advise to use two coats so I would do 2 base coats and then coloring on top of that. It comes in a white or gray powder. The dealer I purchased it from only had gray but the colors seemed to turn out fine. Also, it sets up/drys pretty quick since the coats are so thin. I did wait 2 days between base coats but when I applied the layers of colors, I only waited about 2-3 hours to make sure the previous color was dry. Another great thing is your project doesn't 'grow' as you add SikaTop. I know with concrete you need to allow .5" or more to accommodate for the layers of cement you add versus SikaTop you end up with maybe 5mm.

One thing I forgot to mention in my process is that once the styrofoam was carved out (before adding layers of SikaTop), I used a small blowtorch (plumber's torch) to 'stabilize' it. It melts the outer surface of the styrofoam and hardens it...this really seemed to add to the foam looking like rocks. I burnt a few big dimples a couple of times and also the silicone caught on fire a little, which further melted the styrofoam, but it all added character to the project :wink:

Sorry for the long post, but as I typed I kept thinking of more things to add

Hope this helps!

 

[SoonerCichlid]

Thank you so much for your reply; it really helped. Your route really seems like the best approach for me, but I am also using bface1212's idea by starting w/actual rock and siliconing styrofoam pieces to the back of them, then cover the foam w/the sika product you are recommending, and lastly siliconing modules to the back of the aquarium. I have already laid out my rock pattern and glued the rocks to the styrofoam boards. Tonight I am cutting the foam around the rocks to give it the rock-like looks, then I will be going to a sika dealer nearby. I am so excited that I found your post, less curing time=more enjoyment
I wil post my project upon completion.

 

[SoonerCichlid]

Did you coat the back of the styrofoam or just leave it bare? I didn't knnow if it would flake off around the edges if left bare.

 

[R-DUB]

Awesome BG!! Also way to go using a different product. Concrete is such a painful process. It also hides so much detail. You did a great job. Thanks for the tips

 

[rchickering]

Did you coat the back of the styrofoam or just leave it bare? I didn't knnow if it would flake off around the edges if left bare.

The styrofoam I bought had plastic on each side and I ended up just leaving it on the back for the piece that sits against the glass. On every other surface, I took as much off as possible (sometimes it came off in big pieces and other times it barely tore off).

Thanks R-DUB for the positive comments!

 

[dreday]

i used a similar product for my bg. it was a surface bonding cement.(cant remember name) worked really well and dries in 1 day. much easier than cement were you have to wait for so long to let cure. also i highly doubt that it raises ph at all. these products harden quickly with no residues or leaching. the aragonite sand will buff the ph more than the bg.

i just wonder how much silicone you used to get it to stay down. that was my problem. i used tank sealer and after 8 months it wore of and the bg started to float. i just took it down last week because it was pushing my overflow boxes up and was looking shoddy. all the styro is hard to keep down.

and did you use anything to weigh it down besides the silka top??? and really how much silicone did you use?? i would like to make another bg that would stay down this time. :fish:

 

[R-DUB]

I am also wondering about how you got it to stay put. My BG will have no concrete at all. Just Drylok on the styro. So I have absolutely no counter bouyancy! My styro is about 23" tall and an average of about 2" thick. (thicker in some areas and thinner in others) I am really worried that just silicone will fail over time. The entire back of the BG will set flush to the glass and towers with no voids. Im hoping this will provide enough surface area for it to hold well. Any advice would really help thanx.

 

[rchickering]

I used almost an entire tube of silicone. I applied it around the perimeter of the background and then made smaller rectangular shaped applications (total of about 5). My thought process behind this was if an outer seal failed, it would hopefully stop water from getting behind the entire background.

I also applied some extra silicone here and there and after the project was on the back of the tank, I put a bead of silicone along the top of the background.

As stated before, the plastic that came on the styrofoam (I assume this is a moisture barrier for when the styro is actually used in a wall for insulation) was left on the backside of the the background. As hard as it was to remove this from the pieces I did not want it on, I am hoping that will help secure everything to the back of the tank.

My background is about abou 45" wide and 28" tall. I didn't use anything else to hold/weight it down.

At one point during construction, I thought about somehow making 3 or 4 very small holes about 8" up from the bottom of the background and running some heavyweight fishing line through it and then securing that to the lightgrid I installed on the bottom of the tank. The larger rocks I purchased weight a total of 100lbs plus the substrate. This seemed like it might be a lot of work to do and I wasn't sure exactly how I was going to do it so I gave up on the idea.

 

[R-DUB]

I like the idea of using a perimeter of silicone. That way no water will make it to the inner areas. Very smart, mind if I steal your idea? LOL
:thumb:

 

[dreday]

ah i also like the string idea too. i have 160lbs currently and could use some more. that should hold it down... :drooling: