DIY - Projects & Ideas • Diy lightwieght concrete background (56k beware)

[Exodus1500]

I LOVE that you are going with a natural design. Often I like setting up a tank just as much as I enjoy the fish in it.... I am a huge fan of aqua scaping. Im sure it would be difficult, but if you could make a few of those stalagmite looking formations freestanding in the center, it would look amazing. actually, if you formed them with some sprayfoam and then used your cement technique it probably would go over easily enough.

[iceblue]

Actually, I'm useing a lightweight concrete mix to stay away from sprayfoams and styrofoam allthough I may use a sprayfoam to disquise my overflow boxes. It's much easier for me to design caves into these structures and I don't have to worry about anything floating on me or the styrofoam degrading over time.

If you look at the second to last photo I posted you can see the base of one of the structures I'm going to use to split the tank into thirds. My undergravel jet system will be circulating water counterclockwise in each of the three sections with the center structures seperating them. My return lines from the sump will be at each end of the tank one at the front and one at the back about halfway down and pointed towards the overflow boxes also located one to the front and one to the back opposite the returns. This arrangment will also keep the water moving counterclockwise. The center structures will be at different hieghts along this flow pattern and I'm hoping this will along with the jet system give me a kind vortex pattern that will aid in keeping detritus off the bottom of the tank and flowing towards my filter.

[Exodus1500]

Please, forgive my ignorance here, but don't you have to apply some sort of sealant over the cement, lest it will leak toxins?

[iceblue]

The biggest problem with concrete/mortar backgrounds is the leaching of minerals that raises your hardness to very high levels. I'm hoping to avoid this by having a very long curing time before adding water. Once I do add the water I will also be doing a very long fishless cycle. This should establish bacterias and algae on the structures and seal them further. I'm thinking I'll be feeding the tank ammonia for quite a while while I save up for the fish stock I want to get.

I know that back in the 70s when earth sheltered homes were becoming popular some of them had a problem with radon emminating from the concrete walls. But that had more to do with where the rock for the concrete had been mined than with the cement itself.

[iceblue]

Well... I finally got the back wall done. There is nothing fast when it comes to building these things but I'm real happy with the results I've gotten so far.

While waiting for the concrete to dry between steps I've been buttoning up a lot of things on the tank. When the background is done I'll no longer have any excuses not to get the glass and fill it up with water.

This is a pic looking down one side of the tank in ambient light.


This one is with my lighting system on. I'm real happy with these security lights. Thier 6500k with a CRI of 92. It's a very clean light slightly in the blue range. Thier are 2 of them and they use only 65watts each but give you the equivalancy 500 watts of lighting per bulb.


I know a lot of people are fat on LEDs these days but I just love the way my cold cathodes light up this tank. There are 6 of them and pictures just don't do justice to what they look like when your standing right in front of it.

[Mcdaphnia]

That last shot of the "Pagoda stones" looks even more like basalt.

http://www.spokaneoutdoors.com/basalt.htm

Some volcanic rock has a similar appearance.

http://www.lindahall.org/events_exhib/e ... n/50.shtml

[iceblue]

That last shot of the "Pagoda stones" looks even more like basalt.

Early on in this tank project I spent a lot of time looking for geological maps of the Lake Malawi area. At the time I wasn't really sure what direction or method I was going to use to build the background but I did find a very good map showing the type of rock that overlayed most of the area around the lake. By the time I did decide what I was going to do I no longer could find the link to the map. I tied a rope to my ankle and and threw it over my shoulder and began pulling on it for not saving it to favorites or something. It would have at least allowed me to make a pretty good guess as to what the formations were.

Malawi is a mixed bag of rock type and all in all I'm still happy with the direction my projects going even if it is a bit styleized. If only I knew what color/s they were....

[Mcdaphnia]

.... If only I knew what color/s they were....

Green! That's what they mean by Aufwuchs.

https://www.cichlid-forum.com/articles/aufwuchs.php

[iceblue]

I'm hoping thats what I get eventually but I'm not sure if my lights will be strong enough to punch down to the bottom of the tank to maintain a healthy crop.

[Mcdaphnia]

:lol: I'm hoping thats what I get eventually but I'm not sure if my lights will be strong enough to punch down to the bottom of the tank to maintain a healthy crop.

Basalts and similar volcanic rocks are often dark gray or brown. They may be reddish or yellowish due to other minerals. I threw lots of oak leaves in as my rocks naturalised. Some rocks turned dark brown while others or parts of the same rock stayed gray. I didn't expect it to be permanent, but almost a year later, I could still see the color differences. Hopefully your ammonia treatment will also encourage some green as well as beneficial bacteria, and oak leaves during the fishless cycle shouldn't hurt anything though they are slightly acidic (tannic acid). I had plenty fo algae growing right on the leaves.

P. S. Some cool geology maps of Lake Malawi here:

http://rock.geosociety.org/limno/files/ ... l_2006.pdf

[iceblue]

Hopefully your ammonia treatment will also encourage some green as well as beneficial bacteria, and oak leaves during the fishless cycle shouldn't hurt anything though they are slightly acidic (tannic acid). I had plenty fo algae growing right on the leaves.

P. S. Some cool geology maps of Lake Malawi here:

http://rock.geosociety.org/limno/files/ ... l_2006.pdf

You got me to looking around on the net again and now I have a headache. Trying to learn geology in a couple of afternoon sittings is near impossible. Closet I could figure out is that they could possibly be precambrian columnular igneous basalt. Minerals and organic growth also play a role in the actual surface color of the stone. I've decided to paint them to match some of the basalts from Wisconsin. Should make for nice looking formations. http://images.search.yahoo.com/search/i ... 0&ei=UTF-8

Oak leaves are in short supply here in Vegas although I can get my hands on plenty of pine needles. I know thier on the high end of acidic but I'm worried about thier high resin content also. I may just have to stick with a long cure time before I add water and plenty of water changes after cycling the tank.

[jcollette3]

Looking good. Are you going for a columnar basalt look? Columnar joints form in slowly cooling flood basalts (where large volumes of basalt issue from cracks int he ground and cover vast regions from 10's to 1000's of m thick). As the basalt body cools, contraction occurs within the body, starting from both the bottom and top of the flow. This contraction is spread throughout the body, and since the lava is already partially solidified, it cant move about, so small scale cracks and planes of weakness form as a result. These things can be spectacularly geometric. Here are some images I found on a quick yahoo image search.





The color is caused by oxidation of metals that are contianed in the basalt, primarily as Fe and Mg. The color is usually a nice deep red brown, but whack a piece open with a hammer sometime. The interior is a deep steel gray. If you have any other basalt or rock related questions send me a pm, I'm a geologist.

[iceblue]

Well... I have an update on progress. All the structures are done and I'm ready to paint/color. As I had stated earlier, thier is nothing quick about building backgrounds this way. If you don't have patiance I wouldn't recommend it.

Here are a few pics showing the structures that divide the tank.

Left of center.


Right of center.


A couple of randoms.




These are the frames I built to hide the pumps that will be feeding my UGF. If I have a problem with the pump the whole structure will be easy enough to pull out and up to perform maintainance.


Here's one of them in place and being covered with the concrete mix. The grey tube is to hold the outlet for my return line from the sump in place and, in the direction I want the flow to go.


Front and back view of one of the false fronts after they were completed. Both of them stand up on thier own amazingly enough. The shelf at the top is for mechanical filter material, probably a course sponge.




Side veiw.

[nicholas316]

not bad!

[remarkosmoc]

WOW. That is really nice, I've never had the skill or patience for sculpting. Good job. Please post pics of the finished project when it's done.