Diy rock help please

Reef Aquarium & Tank Building Forum

Help Support Reef Aquarium & Tank Building Forum:

P

panther_119

Well-known member
Joined
Feb 6, 2012
Messages
61
Location
parkland/tacoma, wa
I have been trying to make my own rock. I have been using 4 parts crushed oyster shells(calcium based it is all i can find in the feed stores around here), 2 parts salt, 2 part portland cement, 1.5 part water. i have been using the salt as the mold also. i leave it in the mold for about 6 days before i take it out. since it isnt summer time. it is completly dry when i take it out. but when i put it in water, it completly falls apart and turns to mush whithin 24 hours. i have tried different varient parts to this formula all with the same result. i have no idea what im doing wrong. i need help please.
 
I am not 100% sure, but when you mix your cement, shells, then add water. right before you put it in the mold add the salt cut that down to 1 part. I would also use a sand bed as a mold instead of the salt. From my understanding the more salt that is used in the mix the more brittle the rock will be. Dont give up. Try different recipes and take notes on them. The rock should be cured enough with in two day to remove it from the mold.
What type salt are you using? Rocksalt? softwater conditioner salt? Tablesalt?
 
I am currently using softwater conditioner salt (sollar salt). I also wateched a You tube video by john c. that said the calcium based Oyster shells break up very easily, and to only use the 100% oyster shells. however i have been all over tacoma at the feed stores and have only found calcium based shells. does anyone from other places know of a feed store that sells 100% oyster shells?
 
I saw that video too:) It's a good one but you can use crush coral in lieu of shell, also reef sand, white cement, large grain salt, and if you want bigger pieces/rubble rock in the mix. Look at Jehmco.com under aquascape section for # 15 size coral pieces you can get rubble rock from tons of places. Also you can mix in Perlite with your mix gives strong poures rock also you can find information on the web for this:)

Best of luck!
 
i have all the supplies u need to make 100+ lbs of rock if u wanna come by and swoop it up make an offer ar open to trades let me know i have extra course rock salt 100% oystershell and 90 lb bag of white portland 2 cement.
 
+1 on the taking a look on the salt being the prob. especially using salt for the mold. the salt may be pulling moisture out of your mix before it has time to cure. just like if you are going to poor concrete in a freezing temp you can use antifreeze so the concrete has time to cure, before it freezes.
 
I just made some rock of my own this weekend. I used Portland Cement, Crushed Florida Coral, and Ice Cream Rock Salt from the grocery store. I rinsed the coral out until the water was clear and strained it, added the cement and mixed it in really well while the coral was still wet, added in some water and mixed. The orignal mixture wasnt thick enough for my liking so I added in one handful of cement in at a time until it was the consistancy I needed. Then I put the rock salt in and gave it one more mix. I made one corner rock with just free form in a cardboard box and a second using salt to great large caves and both came out really strong. I am soaking them now and have been for a week and they are still strong. Should be ready to go in my tank a couple weeks after we get to Hawaii.
 
Hey just a heads up on the use of crushed coral and/or oyster shells. When any critter that creates its own shell it uses alot of organic Phosphate in the process, now this P is tightly bound to with in it (as in it wont come out of solution easy) but with rock your going to get alot of areas of anaerobic areas (pretty much the whole interior) and under those conditions the P will begin to leach into your system and will so for a long time.

You can some what cure the issue with oyster shells by heat treating it (they do this to leach the P out prior to using it for chickens and such) but you need to get up in the 700's in order to do it. Maybe a tiger torch?? I am not sure it that will work on the crushed coral (which contains a fair amount of snail/scallop/various shell types) but in testing you can get a mg of P out of a simple 1 kg bag of it.

I am not saying to do it, just wanted folks to know as many facts prior to jumping in.

Mojo
 
Thanks Mojo, I already did jump in and made the rock, LOL. I make it for a small 4g pico that I didnt want a bunch of rock in the center, instead I designed the rock to form around the back and side wall of the tank and to hide my plumbing for my sump. I have heard that it takes a while to cure the rock and I have started doing that already. I do about 5-10 water changes a day on the rock to try and speed up the process. Now back to the Phosphates, will running a phosban reactor counter this higher phosphate level? I will be running a fish only tank as you cannot have corals in Hawaii. Thanks again.
 
A Phosban reactor is one way, but that is only when you see an issue so let it go and just keep an eye on it. I can see the advantage as Hawaii is not a cheap place to get rock. On the curing keep an eye on the Ph of the water you are changing out as that will tell you how far along you are.

Good luck


Mojo

Sent from my AT100 using Tapatalk 2
 
Yeah, no kidding. I will hook up with Les when I get settled in and he said he can direct me to what I need. I will be checking it when I get to our new place as the water will be different there than here in washington but figured I would start soaking now to get things started. Thanks for all the help Mojo, appreciate it.
 
chickenofthesea said:
Thanks Mojo, I already did jump in and made the rock, LOL. I make it for a small 4g pico that I didnt want a bunch of rock in the center, instead I designed the rock to form around the back and side wall of the tank and to hide my plumbing for my sump. I have heard that it takes a while to cure the rock and I have started doing that already. I do about 5-10 water changes a day on the rock to try and speed up the process. Now back to the Phosphates, will running a phosban reactor counter this higher phosphate level? I will be running a fish only tank as you cannot have corals in Hawaii. Thanks again.
Click to expand...

That size of a rock would fit in the toilet tank. Just think how many times a day the water will be changed!!
I have read where people have done this with good results.
It will take longer than a few weeks to cure your rock.
Mojo said it best , test the water for ph before use.
 
I was thinking about doing that with the toilet tank, good idea. I do realize it can take a considerable amount of time to cure it and I have no misconception that I will get to Hawaii and throw this rock in my tank right away. I have 3 years at this next duty station so I am taking it nice and slow and trying to get things dialed in just the way I want them before I throw live stock in. Thanks for the advice!
 
Last edited:
The texture of the rock looks good. I can see all kinds of holes. Dont be satisfied with one and done. Now that you know how to shape it . Do some more.
How many bathrooms does your new place have?
 
You must log in or register to reply here.

Similar threads

alki
Reef Setup looking for new home
Replies
1
Views
587
Katchupoy
Katchupoy
CJG
Tanks for sale
Replies
0
Views
541
CJG
CJG
barrierreefcf
Barrier Reef's Mid-Remodel Sale
Replies
2
Views
1K
barrierreefcf
barrierreefcf
C
Need help with cycling tank
Replies
2
Views
2K
Scooterman
Scooterman
barrierreefcf
Please Read - Helping Mike Foote
Replies
2
Views
1K
Scooterman
Scooterman

Latest posts

Back
Top