making base rock

[lsplitte]

has anyone noticed the fake rock at public aquariums. I talked to one of the marine biologists in Omaha, Nebraska and he said that it was made with a fiberglass compound. Does anyone know where to buy it or DIY?

 

[huig]

hello
there are several ways, making base rock.
a. just use limestone from a garden centre
b. cement (see GARF website)
c. polyurethane foam (in a bottle) covered with epoxy varnish or polyester top coat (mix with non toxic colouring agents) one can add glasfibre
c and b have the advantage that the only limitations are your imagination.
the drawback is that these methods are laborious and you need to cure the material before use
a is the easiest way to go, you simply buy the rock, clean it and you're ready to go.
greetz

 

[pkolenda]

Most of the stuff you see in large aquariums is pretty expensive and made by artists. Making it would be very time consuming to get the colors etc. Plus since it is not real rock, it would not become “live”.

Your best bet is to make rock as mentioned above or buy a pre-made structure.

I am a fan of building a structure with PVC then covering it with Rock. When I did it in my tank I made sure the structure was all connected and drilled holes in it. So, when I clean the tank, I can attach a powerhead and blow junk from under the rocks.

One store by me uses PVC for arches etc. He takes a long piece of PVC and bends it. To bend it he heats it with a heat gun. (the type you get a Home Depot etc)

Good luck. If you build your own rock let us know and post some picture.

 

[bond007069]

Man, i made some agrocrete rock using GARF.org instructions, in like Sept 2003 and my rock still has not stoped lowering my freshwater pH to like less than 6.0, been curing for like 6 weeks, but still leaching harmfull chemicals in to freshwater, i am getting real impatient. :? 8O

 

[pkolenda]

I know some people that have used bricks as bases in the back of the tank.

A couple of stores by me also see rock that looks similar to live rock but is not live rock - pretty cheap.

That might be an option.

 

[doc_slick]

Don't rush the aragocrete curing process. I make this rock professionally. I will not sell it unless it has cured 14 weeks in freshwater changed every day. There are ways to cure this faster, but even GARF's artist Eddie Postma cures his rocks for 12 weeks before he sells it. If you place this rock in your tank before it is fully cured, it will outgass and lower the ph until it has cured completely. Hope this helps.

 

[Dewman]

What do you think about setting your aragocrete Live rock in a swift running stream in a bag made of netting and then leaving it there for 2 months and coming back to get it? This way, you could set it and forget it and not have to mess with water changes all the time.
When it has cured, you can just submerge the rock in a bleach solution and rinse it.
Could this be an option?

 

[doc_slick]

This has been suggested by several of my collegues. I believe that this would the ideal way to age this type of rock, however. I would not use a bleach solution afterward and would soak the rock overnight in some freshwater and test the ph of the water again just to be safe. To kill any organisms that the rock had obtained from the body of water I used, i would bake the rock in a 300degree oven for an hour. ( After scrubbing the surface of course. Then let it cool to roomtemperature slowly. As a matter of practice, i use styrofoam fish boxes with water to cover them changed daily until the hydrometer reads 8.2 or lower. Using a bleach solution could be an unwise step if you were unable to get all of the bleach out of the rock and it's pores. Since bleach is basic and the cement in the rock is basic, you might add to the outgassing of the rock. I always wash my rocks in warm vinegar or diluted muriatic acid as the next to the last final step before drying. the last step is an ovenight soak in saltwater from a tank water change or freshly made. After this step I then usually dry the rocks in the sun.

 

[doc_slick]

This has been suggested by several of my collegues. I believe that this would the ideal way to age this type of rock, however. I would not use a bleach solution afterward and would soak the rock overnight in some freshwater and test the ph of the water again just to be safe. To kill any organisms that the rock had obtained from the body of water I used, i would bake the rock in a 300degree oven for an hour. ( After scrubbing the surface of course. Then let it cool to roomtemperature slowly. As a matter of practice, i use styrofoam fish boxes with water to cover them changed daily until the hydrometer reads 8.2 or lower. Using a bleach solution could be an unwise step if you were unable to get all of the bleach out of the rock and it's pores. Since bleach is basic and the cement in the rock is basic, you might add to the outgassing of the rock. I always wash my rocks in warm vinegar or diluted muriatic acid as the next to the last final step before drying. the last step is an ovenight soak in saltwater from a tank water change or freshly made. After this step I then usually dry the rocks in the sun.

 

[sambo1]

I'm at 4 weeks in two coolers. Figure I got another 4-8 wks. I change the water every 3 , 4 days.

 

[justjoe]

Don't rush the aragocrete curing process. I make this rock professionally. I will not sell it unless it has cured 14 weeks in freshwater changed every day. There are ways to cure this faster, but even GARF's artist Eddie Postma cures his rocks for 12 weeks before he sells it. If you place this rock in your tank before it is fully cured, it will outgass and lower the ph until it has cured completely. Hope this helps.

I don't understand why people are saying the cement rock is lowering the pH, any cement work I have done, and I've done it by the pallet loads, the fresh concrete will always raise the pH to extremely high levels. Dosing with muriatic acid (from pool supply stores or home centers) certainly sped up the process of leaching the concrete. A dosing rate of 1ml/100gal will usually drop the pH 0.1 and you can safely use 10ml/100gal. As the pH slowly climbs back up, the system is redosed and over time less and less acid is needed. This is really caustic stuff, avoid breathing the vapor and wear proper gloves along with goggles. When dosing our shark tank of 120,000 gallons, I would dump 10 gallons/day to intially the pH down. On smaller set ups, white vinegar may also be used, but its not as effective as muriatic. A small dosing pump hooked up to a pH controller will save you the trouble of handling the acid or having to change the water so frequently. With the fresh concrete, I tried to keep the pH around 5 so the concrete was constantly leaching until it was exhausted. Infact the tank was carefully dosed small amounts of acid for a few months after specimens were added as the pH would still slowly climb in the beginning.

 

[BRose]

You're correct. Intially, cast concrete raises the pH. It will tend to raise the pH in water until it's close to 12 in newly cast concrete.

From a Dr. with a PHD in Concrete Analysis:
The pH level is a measure of acidity or alkalinity, on a scale of zero to fourteen, with zero being most acid, fourteen being most alkaline and seven being mid-range.
Regular concrete has a high pH when it is first cast. This is caused by excess calcium hydroxide in the concrete. Calcium hydroxide is a hydration byproduct which typically has a surface pH of around 12 for normal concrete when cast. Over time, in water, the calcium hydroxide slowly leaches out. Eventually, the pH of the concrete will approach the pH of the sea water which is about 8.3. How long is dependant on the pH and disolved ions in the water and the thickness of the cast concrete.

Cheers, Bill