DIY Aquarium Rocks

(a compilation)

I have been doing some research on making my own aquarium rocks and have found several interesting ideas. here is the recipe that I am going to try. recipe for home-made rocks: One part Portland cement. [Type 3 is best, but 1 & 2 will work] (FYI, Portland Cement is the TYPE of cement NOT a brand name - usually found at any decent hardware store) Four parts play sand. [Washing the sand will make stronger rocks] (but I have also read that just about any type of sand or fine gravel will work)

AND enough "EXTRA" sand to use for molding. (also the use of fine gravel is acceptable)

Mix cement and sand together to a pasty consistency.
It should form balls in your hand.

Cement is very alkaline, so use rubber gloves when handling. Place a fair amount of damp sand into an appropriately sized container. Dig holes in the damp sand to form a mold. You choose the shape. Drop the cement mixture into the mold and form it with your hands. Additional damp sand can be used as a filler to create caves, tunnels and holes. Let sit for 24 hours before touching. Cure the rock! Cement is very alkaline and will raise your water's pH. I'll let you guys know how it turns out.
- FishPimpin73

I think Diver has talked about a process to drastically reduce the alkalinity of 'agro-crete'. I'm sure it would probably work on the type of cement you're talking about.
- Pyrowolf

Make sure you cure it for 6 weeks minimum and change the curing water daily. Using a powerhead in the bucket will also speed the curing process. If you cure it long enough it is said you can leech all the alkaline out of it making it neutral but it may take up to three months of curing. I actually wrote a good long post on how exactly to do this for FW and SW on the old sight but it got cleaned out a month before the move.
- Diver_J

Now, DJ..... The site where I got this recipe states (along with several other sites) that this specific kind of concrete can be cured in a week??? Using freshwater everyday for 5 days. Also, there are several sites, on everything from ponds to aquariums, that say the same thing about Portland Cement......
- FishPimpin73

These guys are the ones who wrote the book on using cement to make Rocks for fish tanks and they say cure for six weeks to eight weeks. http://www.garf.org/class.html#mold

Quote:
When all of your rocks are complete then it is time for them to be cured. Leroy Headlee recommends putting the rocks into a kiddy pool or another container that will hold all of your rock and enough water to cover them. In the kiddy pool you can run a garden hose to the pool and poke an exit hole to water any thing else in your yard. We recommend water change daily or as much as possible (the more the better) for six to eight weeks. If you do not cure the rock it will mess-up the pH levels in your tank, which can be detrimental to the life in your reef.

For more rock making reading see here: http://www.garf.org/howtodoinformation.htm#Aragocrete
- Diver_J

yeah I have been to both of those sites.
5 to 6 weeks huh???
I think that if I do t
his that I should just keep testing the waters PH till it goes neutral.
- FishPimpin73

Oh defiantly try it. Also do not use aragonite sand or crushed oyster shells these are slow leechers which will keep your PH up when making rocks. You want to keep your sand and anything else you mix into the concrete neutral so the PH from the cement is the only thing you need to neutralize.
- Diver_J

Nod, yeah I figured that. I have found some really cheap (100lbs = $25.00) fine gravel that I plan to use. And maybe some neutral water?? hhhhhhhhhrrrrrrrrrmmmmmmmmmmm I wonder?? I'll let you know how it goes.
- FishPimpin73

I don't know how much of that you have read through but you can make Texas holy rock and some sweet caves by using Pasta, rubber gloves, or balloons. - Diver_J

Yeah the garf guys have some really cool ideas.
And there are quite a few other people doing the same things.
- FishPimpin73

ok but if your ph is low and your wanting to raise it? Mine, in the sw tank, has dropped to 7.5 can I cure it for less time and put it in the tank to raise the ph to over 8.0?
- Gal5

Well, yes... sort of. Just keep in mind that as it is in the tank... it will slowly bring your pH back down because the alkalinity will start to go down as it hangs out in your tank. I'd recommend some CC (crushed coral) in your filter to give you a better long-term pH helper
- Pyrowolf

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