ok after the cement is done curing, wouldnt it be more beneficial to use water straight from the ocean since it is already teaming with life? the ocean is a ten minute drive from where i live..
Actually no. "Curing" has different meanings in this instance. When we use "Curing" to refer to the process of converting dead base rock to live rock, the process involves allowing life to grow on the dead rock. When we say "Curing" to refer to the process of allowing the concrete in man-made live rock to set, the process involves waiting for the rock to stop leaching lime into a water column thus DRASTICALLY raising pH.
When allowing home-made LR to set, the concrete can and will release lime (carbonate and bicarbonate) at an exceptionally fast rate. The speed with which it releases this lime will often raise the pH of the water in the containing vessel clear into the 11-12 range. At that exceptionally high pH, most organisms don't exactly live, thus removing any benefit from life from natural seawater. Furthermore, if you put natural seawater in the tank that is curing the LR you will get nasty calcium carbonate deposits everwhere as the high pH will result in a precipitation of calcium and magnesium salts out of the seawater. Its pretty much a chemistry nightmare to try and allow concrete to set in seawater, you want to stick to fresh
.
That being said there are really 3 common methods of "curing" home-made rock and allowing it to set that have any merit.
Toilet Method - If your volume of rock is relatively small and you've got one of the "old-style" 5gallon flush toilets (pretty much if it was made pre 1990), then you can stick rocks in your toilet cistern. There they will get constantly flushed with fresh clean water and is a great fire-and-forget method. Only caveats are if you have a large volume of rock you cant do it, or if your tapwater has significant copper in it dont use it. Usually takes 3-5 weeks.
Stream Method - Set the rocks in a container made of grating like an old milk crate or bottle crate that basically has mesh sides. Then sink it in a nearby stream. This method is another great fire-and-forget method. Only caveat is if the stream/river is not very clean and prone to pollution, then it might not be a good idea. Again, 3-5 weeks.
Manual Method - Setup your rocks in 5g buckets or big plastic bins and do large daily water changes. Try and keep the pH down below 10 (ie once it gets to 10 or higher do a water change) which usually involves daily changes early on, stepping down less often as the rock gets more and more cured. The advantage is that if you have pollution in a stream or copper in your tapwater, you can use RO in a clean controlled environment. Disadvantage is time and effort. Takes 4-6 weeks and lots of water changes.
In your case, the only other option I could see would be to sink crates of LR in the ocean itself but complications like tides, ocean current, high waves, authorities and other problems would prolly prevent that.
