DIY Reef Rock Formed to an Overflow

[Jason Rhoads]

I wanted to share a DIY project for making your own rock to help hide those big overflows.

 

DIY rock is a great choice for a project like this because:

• It is low-impact
  
• It is totally customizable
  
• It is pest free
  

In my case I wanted to cover the overflow of my 90g bow front but I didn't want the rock scape to take up much space. Due to the curve of the glass there was not much room to stack LR around the overflow so I had to come up with a way to maximize my tank space. Using a 5g bucket as a mold I was able to create a rock formation that fit the curve of the overflow and looked very natural.

 

**Full disclosure:I have not yet put this rock into the tank because I misjudged how much rock I had and ended up with too much rock in the tank. I will be using this rock in my 100g build (look for it Feb 2013).

 

The mix I used consisted of:

• Portland Cement
  
• Crushed Oyster Shells
  
• Rock Salt
  
• Old Tank Sand (dry sand left from an old tank)
  
• Dry Live Rock (I included these for aesthetic reasons, they are not needed for biological function)
  

I will not go into a ton of detail around how you make the rock as this can be found elsewhere

 

I will say this though; be sure to preplan the shape you want. Negative space is more important than "rock space" when building DIY rock as that is where you will be filling with sand/shells/rock salt.

 

The first pic is of the overflow that I wanted to mask using the rock.

 

Next pic shows the 5g bucket being used to mold the back of the rock into a curve:

 

 

This shows the shape the back of the rock took once hardened:

 

A close-up of the rock, this shows how the salt is used to form negative space in the finished project. Where you see rock salt will be a cave when the rock is cured:

 

A view of the front side of the rock:

 

 

Tank with one rock piece in place I really like how many overhangs and aquascaping options that are created:

 

I actually have pieces built that (when stacked) allow almost the entire overflow to be covered, but I do not have pictures of those as I was in the middle of a move when I built this batch of rock. Forming the rock to the curve or my overflow allowed me to reclaim some space in the tank. I can use the many shelves created to grow corals or provide shelter to fish/inverts. Having the rock sit snugly against the overflow allows shelves to extend without hitting against the aquarium glass.

[PotomacBoater]

I really like this design

(and the rock salt to create caves is inventive)

 

My tank came with a molded rock overflow cover.

But when I upgrade, I'm already thinking about how I can reproduce the effect

 

Thanks for sharing.

[Der ABT]

aw man i just threw my overflows away or i could let someone have them for the correct curves etc....guess you can always get some abc plastic heat it up with a heat gun and mold it etc...or a gallon milk jug

 

cool idea though.

[countryboy]

Very neat idea! Thanks for posting

[jimlin]

cool idea. wonder if it will work for a cpr overflow.

[Jason Rhoads]

cool idea. wonder if it will work for a cpr overflow.

 

I actually know of a guy (in my NC reef group) who made rock to cover something similar to a CPR. Although he built an entire back wall out of DIY rock, I bet you could make it work. I will try to dig up his old build thread and post it here.

You would probably have to rough up the acrylic to get the cement to hold.

[Der ABT]

or use a plastic rod bent over the top and covered with a rock to make a virtual hanger and just have a little rock out of the water (risk snails etc getting up and over a little more though)

[Coral Hind]

Nice job! I'd like to see some pictures of it in the tank with water.

[monkiboy]

awesome share, thanks for the info and ideas!

[steveoutlaw]

cool idea. wonder if it will work for a cpr overflow.

 

If you moved the CPR to one corner of the tank you could pyramid some rocks up to the overflow and then rest the overlow rock cover on the top.

[DCReefer1964]

I have done this in the past. Back then it was known as GARF DIY rock. Never used salt, but used packing peanuts, Salt is a great idea. How about the curing process. How long do you estimate it will take to get a constant low PH reading?

[DCReefer1964]

http://www.garf.org//_2008/NAMES/index.htm

[Jason Rhoads]

Yep GARF is where I got most of the tips for the project.

 

I estimate about one to two months of cure time is needed. I start by adding about a cup of vinegar to some tap water (probably around 5g) which is exchanged every week. I only add the vinegar for 2 weeks/changes so that the rock doesn't get too weak (I have never seen a problem with the rock getting weak, but have read that it can). Honestly I didn't test the PH until the second month and I forgot a few water changes in that time span, so not totally sure on the cure time needed, it could be less

[DCReefer1964]

Yep GARF is where I got most of the tips for the project.

 

I estimate about one to two months of cure time is needed. I start by adding about a cup of vinegar to some tap water (probably around 5g) which is exchanged every week. I only add the vinegar for 2 weeks/changes so that the rock doesn't get too weak (I have never seen a problem with the rock getting weak, but have read that it can). Honestly I didn't test the PH until the second month and I forgot a few water changes in that time span, so not totally sure on the cure time needed, it could be less

I did the same thing.Never experienced rock breaking down. A few small chunks when I first handled it. I actually used the small chunks to keep the PH up in my African tank.