My first attempt and anything DIY for my Aquarium

[ShadowFox]

After watching what feels like every video on youtube, I decided to try and make my own decorations. I decided on the tried and true styrofoam/cement method, and also decided on doing a sandfall. I have made a huge mess and did a lot of second guessing the look, but as of now, I like where it is sitting.

I have used about 2/3rds of a 4x8 sheet of 3/4" stryofoam, 2 tubes of 100% silicone, and maybe 1/8th of my 10lb bag of quickrete mortar mix. There is only one coat on it now, but it will get more. I carved out a couple small areas on the top flat rock to maybe add some small fake plants.

- There are two tunnel entrances for the fish at the front. Its pretty much a big "U" that goes through the structure.

- The taller rock structure conceals the 1" pvc pipe that will transport the sand, drop it, and hopefully all the sand falls into the "bowl" in the center, which will recycle the sand.

 

[Delapool]

Looks nice and like the layout. How long did it take?

 

[ShadowFox]

I probably have 6 hours into it right now. Most of that was because I wasn't sure what look I was going for with the styrofoam, and a lot of trial and error with looks. I think it looks a lot better in person. For some reason the pictures make it look like a big concrete blob. The lines are more defined inperson

 

[Delapool]

I like how you would get exactly what you want as well to fit the tank.

 

[Mebbid]

Amazing looking formation!

 

[lunch]

Dude that looks sweet as

 

[richie6]

Nice! Waiting to see the final pictures and install.

 

[ShadowFox]

My final coat just went on. I added a dye to the concrete which made it a lot darker. After the original coat fully cured, the color was like bleached jeans. I am going to Presoak it and test it in a extra aquarium that is lying around, then it's going in my dad's 55 gallon, which I am redoing for him for Christmas. I will definitely keep you posted

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[Delapool]

Are you testing water chemistry out of interest? Would be interesting to see what ph does.

 

[ShadowFox]

My plan is to test the tap water ph, then the water every 24 hours after submerging it, and doing water changes every day until tap PH is the same as tested PH

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[ShadowFox]

Then when they are the same, I'll transfer it to its permanent home

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[Delapool]

Can you post results? Would love to see what it does if possible.

 

[tedisabum]

Boss level.


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[ShadowFox]

Ran into a little bit of a snag...never underestimate the buoyancy of styrofoam. I have a large tote that I am trying to presoak this structure in, and it is doing its best boat impression. I know that there is a LOT of styrofoam involved in this piece, but I thought that 4 layers of cement would weigh it down. I was wrong.

The good news is that I never used cement on the bottom of the structure, as I wanted to see how it worked in the tank with gravel or sand. Hope this makes it simpler to modify to work. I am trying to find some type of buoyancy calculator to see if it would be more beneficial to simply hollow out as much of the structure as possible, or carve holes out and fill them with cement or rocks. Suggestions?

 

[ShadowFox]

*Update

I am currently at work, but have rough dimensions of my structure, and estimate it to be ~1 cubic foot of styrofoam. Which from what I have looked up is that I will need 64 lbs to make it sink. The volume of the structure does not include the areas that are hollowed out for the caves or bowl. I think that I am going to carve out areas underneath the structure and fill them with concrete that I have laying around. I may be wrong, but my logic says that if I am able to remove styrofoam (essentially trapped air) and replace the area it used to occupy with something like concrete, I should be able to double the effects on its buoyancy.

 

[tedisabum]

So I looked this up and this is what I found. Buoyancy is the force of a floating object. First you have to know how many square feet of water are displaced after placing the object in the tank. Then, you have to multiply this number by the weight of sea water (64 lbs per square foot). That will give you the buoyancy force of the object.

Buoyancy Force = Volume of Water Displaced x 64 lbs per square foot (Weight of Sea Water).

F=VW

 

[ShadowFox]

That's what I found too. So with the volume of my structure being ~1ft3, it would need to weigh 64 lbs to sink, or at least be neutral. So by hollowing out unnecessary styrofoam on the bottom, I would reduce volume, thus require less weight, correct?

I was also going to fill the space that I vacated the styrofoam from with pure concrete, to add weight. My biggest question is...will I benefit as much as I think I will by replacing styrofoam with concrete? Per the equation, I will reduce weight needed by reducing volume. But by adding concrete, I am increasing volume again, thus requiring more weight. I would imagine the weight addition would outweigh the additional buoyant force

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[ShadowFox]

Looks like concrete is about 150lbs/ft3. I am going to say it would definitely be beneficial

 

[tedisabum]

In my opinion, the theory sounds good. I would imagine that eliminating the buoyant styrofoam for the heavy and sinking concrete should provide enough balance to sink it down. I would only change a little at a time so as not to make it so heavy that it cracks the bottom. You should be able to tell how much more you have to do based on the force you have to put on it when you push it under the water. The less force, the less you have to remove and replace. Good luck

 

[ShadowFox]

Definitely a good school of thought. Thanks for the help!