Jump to content

What concrete to use for DIY base rock


Feelers

Recommended Posts

I've decided that I want to give making my own base rock a go, mainly cost and because I want to build a nice cave for my future octopus.

I've looked of reef central, and found the recipe I want to use, however all the recipies require portland white cement, I know nothing about concrete so what types are acceptable? I went to the wharehouse and saw normal cement, would this be ok? I dont really want white rocks anyway, I happy with the brown playsand coulour look (as this isnt a reef tank).

Has anyone tried making these rocks before?

the recipe I like the look of is, 1 cement, 4 oyster shell, 1 playsand,

Link to comment
Share on other sites

  • Replies 52
  • Created
  • Last Reply

Top Posters In This Topic

I am going to make some myself. Going to use cement (not concrete which already has sand in it), coral sand and coral chunks. That way the rock will still be porous.

Planning on making holes through the rock using various sizes of plastic pipe during construction. I have been told that if you vasaline the pipes first, the concrete will not stick and you can pull them out when the concrete hardens.

I have used normal concrete to join larger coral pieces together. Either way, you need to soak your rock in saltwater to cure it once it is made.

Link to comment
Share on other sites

Years ago when I repiled my house in gisborne, I made the piles myself, using pumice, sand, and cement. This was the procedure in those days to make the piles lite for dragging around under a house, made perfectly fine concrete.

However as to impurities of reef tank significance, that will probably vary from one batch of cement to another. Unless buying a reef tank designed product it is probably not possible to know what may be lurking in the cement.

Garf make concrete plugs for their frags, they first soak them in vinegar, then cure them in salt water for a couple of months. I think this is not so much to establish a biological filter, but more because new concrete can release major calcium / alkalinity and effect these levels in the tank.

IMO the safest plan would be to make a few trial rocks, go chuck them in a rock pool at the beach for a few months to leach whatever they may leach, then introduce to the tank one at a time, monitoring levels and observing livestock carefully.

Link to comment
Share on other sites

Keep us posted feelers and petplanet about how you get on with your rock. I would also be interested in trying out a few different designs. I would also be inclined to use cement aka the portland type which is ready available from any landscape, concrete suppliers eg Atlas concrete.My only concern obviously as well would be the leaching of impurities and lime, but hopefully with enough curing it could be safe. There are other products other than cement or concrete that professional aquarium building companies use. I will try and find out what these are and post it along with the availability.

Link to comment
Share on other sites

  • 3 weeks later...

Hey petplanet is $52 expensive compared normal cement? How big a bag was it?

Does anyone know if standard cement mix has lime in it? Most of the bags I can find don't really list ingrediants. Can anyone reccommend a brand? I might try and find the portland stuff just to do it right.

And about the oyster shells - are you sure this creates phosphates? Would they even matter in my proposed setup?

Is anyone in Chch keen to team up and make some base rock- split the work/cost ? - Layton?

Link to comment
Share on other sites

Trouble is, an octopus makes a heckuva mess. Need a major nutrient removal system in place if this is the means to keep the tank clean.

Only other alternative would be keep the tank dimly lit, or major regular cleaning of the glass and forget about the algae on the rocks.

Link to comment
Share on other sites

Well I'm probably not going to run any "real" lighting. Just leds, I was thinking of white ones, dunno about the wavelength of those or if it could grow algae?

unless he wants to run with man-made rocks, big skimmer and no light until the phosphates drop

well I dont think my weipro can be described as big :roll: haha.

Damn, I just really like the oystershell look. I do remember a thread about the phosphate thing and I think someone ran a test, ill see if I can find it - if rc isnt overloaded - man they are useless! :evil:

Link to comment
Share on other sites

Oh yeah I was thinking of "livening" up my rock in the sea, but I'm a bit worried about loosing it or it being washed away or something. I remember someone suggesting putting it in a washing basket - but you would probably want a bouy, and from past experience thats the best way for it to get disturbed by crayfish theifs.

Link to comment
Share on other sites

Amazing how many guys are sitting up watching their computers this time of night!

:D I was up looking through my tank to see what comes out at night. i've had a look before with a torch but didnt see much. this time i just used the infrared from my digital camera so as not to 'scare away' any unsuspecting guests. how bloody interesting! i'd have to say i have seen worms larger than i ever thought i had, centipede looking things, more acro crabs, crabs twice the size of the acro crabs and more. unreal, its more interesting at night than day! :lol:

Link to comment
Share on other sites

Oh yeah I was thinking of "livening" up my rock in the sea.

I've cured several batches of rock in a rock pool at our local beach. Comes out nice & clean and smelling sweet.

One batch I left there 4 months as I had no place for it, so when I finally got it it had a nice smattering of coraline algae.

Link to comment
Share on other sites

Oyster shells are almost pure calcium carbonate (95-99%) and are good sources of calcium for all classes of animals. Clam shells, conch shells, coral and coral sand can all be used for feeding.

I also read that when they crush the oystershells they just chuck the whole oyster in, insides and all. I think the phosphate comes from the rest of it. The guy who made his oystercrete did some tests and said PO4's were nill. He said that when you wash the shells you can see all the crap coming off.

I think when I get round to making them I'll do some with and some without. Cover my bases.

Link to comment
Share on other sites

:D I was up looking through my tank to see what comes out at night. i've had a look before with a torch but didnt see much. this time i just used the infrared from my digital camera so as not to 'scare away' any unsuspecting guests. how bloody interesting! i'd have to say i have seen worms larger than i ever thought i had, centipede looking things, more acro crabs, crabs twice the size of the acro crabs and more. unreal, its more interesting at night than day! :lol:

Chim, try buying one of these thingsand shining it in your tank at night. Now THAT is unreal.:)

http://www.trademe.co.nz/Electronics-photography/Gadgets/Other/auction-38934349.htm

Hard to get pics though because the water flouresces and confuses the camera.

uv.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...