Tweet
ROCK INGREDIENTS:
2 parts portland cement (90lbs bags at hardware store)
3 parts crushed oyster shell (can get small bags at feed stores. they use it to feed chickens)
1-2 parts rock salt (40lbs bags at hardware store. look for water softener isle) MIX IN LAST JUST B4 POURING INTO MOLD
You can add more or less rock salt to change texture. Also you can add whole oyster shells to add a different texture.
HOW TO MAKE MOLD:
Take a plastic storage bend or anything that will hold sand.
Add childrens playground sand (hardware store has in by the concrete) fill storage ben 1/4 full.
Then make design in sand.
Pour mix into sand.
Cover up poured mix with a light layer of sand.
Let sit for 24hours.
Rinse, and place it bucket of water for a month or 2. (this is because cement is still toxic and so the salt rock can melt and form holes in the concrete.)
After a month or so check ph to make sure its back down to the level of the tap water. ( i always wait till i see mosquito larva in the bucket of water, best way to know its safe)
Rinse and add to tank when safe.
( The best thing about this, is you can make over 100lbs of rock for under 50$)
Mark