DIY rock

[mook1178]

I am planning on making my own rock for my setup. I know to cure it until the pH doesn't change. Then cure it in saltwater as well.

My big question is who has done 90% of their tank in DIY rock and been successful for a long period?

 

[Fish Styx]

@tbrown

 

[tbrown]

I'm probably about 75% Aragocrete.

Here's a few of the pieces I've made.

 

[tbrown]

One thing to consider when curing the rock: new rocks binds phosphates. When you get to the point of saltwater curing, add some phosphates. I didn't with the first couple of rocks I made and saw an immediate phosphate crash and had to dose fairly heavily for a couple of weeks. The next batches of rocks all got saltwater cured with phosphates to get the equilibrium before adding to the tank.

 

[mook1178]

One thing to consider when curing the rock: new rocks binds phosphates. When you get to the point of saltwater curing, add some phosphates. I didn't with the first couple of rocks I made and saw an immediate phosphate crash and had to dose fairly heavily for a couple of weeks. The next batches of rocks all got saltwater cured with phosphates to get the equilibrium before adding to the tank.

I'm planning on starting with my own rocks. So hopefully most phosphate leach will be removed with the first few water changes.

How long have you been running your tank? Have you seen any long term issues other than a phosphate spike?

 

[Stevorino]

I did DIY rock a long time ago and I forget about it mostly except that I consider it a mistake.

What I do remember is that my rock never looked remotely as great as @tbrown 's... and also, I did have phosphate issues long-term and I worried about the rock being the problem.

I ended up tossing it all and just getting dry rock.

 

[tbrown]

I'm planning on starting with my own rocks. So hopefully most phosphate leach will be removed with the first few water changes.

How long have you been running your tank? Have you seen any long term issues other than a phosphate spike?

No spike, phosphate dropped to 0 and I lost a couple of Acros. My tank was started with about 60 pounds of dry rock and 80 pounds of live sand, then I've added around 120 pounds of Aragocrete rocks. My tank has been running for a year and a half with nothing negative beyond the initial drop in phosphates.

 

[tbrown]

Any rock (and sand) will try to equalize with the phosphate level in the water. If there's lower phosphate in the water and higher phosphate in the rocks, it'll leach phosphates and vice versa. Higher phosphates in the water than the rock and the rock will absorb the phosphates. Most dry rock has 0 phosphates so any phosphate in the water will be absorbed until the rock reaches equilibrium with the water.

@Randy Holmes-Farley can probably explain it better than that.

 

[mook1178]

Any rock (and sand) will try to equalize with the phosphate level in the water. If there's lower phosphate in the water and higher phosphate in the rocks, it'll leach phosphates and vice versa. Higher phosphates in the water than the rock and the rock will absorb the phosphates. Most dry rock has 0 phosphates so any phosphate in the water will be absorbed until the rock reaches equilibrium with the water.

@Randy Holmes-Farley can probably explain it better than that.

That makes sense. I was wanting to start with mostly rock I made and adding a small amount of live rock to cycle the tank.

So from the aspect of the rock being a source/sink for phosphate, I should be fine with doing water changes those first few weeks. I should just add phsophate testing as part of my cycle testing.

Thanks for your help!

Oh also, wait until my phosphates settle out once I start adding fish before I add corals.

 

[exnisstech]

I remember reading about @Paul B doing something similar but making structures. My memory isn't great and I can't remember where I read it. May very well have been Paul's book that I read. They looked pretty cool.

 

[tbrown]

That makes sense. I was wanting to start with mostly rock I made and adding a small amount of live rock to cycle the tank.

So from the aspect of the rock being a source/sink for phosphate, I should be fine with doing water changes those first few weeks. I should just add phsophate testing as part of my cycle testing.

Thanks for your help!

Oh also, wait until my phosphates settle out once I start adding fish before I add corals.

Certain corals rely on phosphates more than others - Acros for example. Low phosphate and high alkalinity can be a death sentence for Acros.

Algae can be another concern. 0 phosphates and high nitrates I believe can Cause either dinos or cyano but I don't remember which?

Also also, make sure you use Portland Cement (or similar) that doesn't use silica sand and don't use playground sand (that's basically silica sand).

 

[mook1178]

Certain corals rely on phosphates more than others - Acros for example. Low phosphate and high alkalinity can be a death sentence for Acros.

Algae can be another concern. 0 phosphates and high nitrates I believe can Cause either dinos or cyano but I don't remember which?

Also also, make sure you use Portland Cement (or similar) that doesn't use silica sand and don't use playground sand (that's basically silica sand).

I knew to use Portland cement, but had not looked into what playground sand was, so thank you! What sand do you recommend?

 

[tbrown]

I knew to use Portland cement, but had not looked into what playground sand was, so thank you! What sand do you recommend?

This is what I went with because it's the cheapest I could find on Amazon. Any Aragonite sand or Oolite sand should work. Crushed coral works as well but tends to be bigger and more expensive.

 

[tbrown]

Here's a couple of my old threads from these projects.

EggRagoRack Homemade Hybrid Frag Rack

So when doing research early on in my reefing I came across a couple of interesting projects : Egg Crate Frag Racks and Aragocrete homemade cement/aragonite sand rocks. Egg Crate racks are simple and efficient but not overly pretty. Take some egg crate light diffuser and cut it to size. Using...

www.reef2reef.com

Aragocrete/Egg Crate hybrid DIY Frag Racka

So I started an experiment! I have made some Aragocrete rocks in the past and they're doing swell. I made an Aragocrete cover for my PVC return pipe inside the tank and it's also doing swell. However, there have been some recent discussions about frag racks and I have several egg crate light...

www.reef2reef.com

I didn't do a walkthrough for just plain old Aragocrete rocks but it's the same technique, just without the egg crate. Making it upside down in the sand works better because you can "design" the top better and it'll be a bit more textured.

 

[tbrown]

I did DIY rock a long time ago and I forget about it mostly except that I consider it a mistake.

What I do remember is that my rock never looked remotely as great as @tbrown 's... and also, I did have phosphate issues long-term and I worried about the rock being the problem.

I ended up tossing it all and just getting dry rock.

I used Egg Crate to form frames for some of mine. It's helped with structure. Glass/acrylic rods can be used as well.

 

[John K]

Too bad Southdown is only a memory now. This must be a good bit more expensive now....

 

[tbrown]

Too bad Southdown is only a memory now. This must be a good bit more expensive now....

I think I spent $35 for th cement and sand - enough for 100+ pounds worth.

 

[mook1178]

Thank you so much for all the info and help.

 

[tbrown]

Thank you so much for all the info and help.

No problem! That's what this forum is all about.

 

[Dburr1014]

I am planning on making my own rock for my setup. I know to cure it until the pH doesn't change. Then cure it in saltwater as well.

My big question is who has done 90% of their tank in DIY rock and been successful for a long period?

I used Portland type 2 cement and oyster shells years ago. I slowly swapped it out for real rock but there are still a couple pieces in my system.
You never have to worry about po4 dropping off with oyster shells.
But sand will look much nicer. Maybe mix sand and shells?