Live rock is generally agreed as being the best filtration medium for the marine aquarium. It’s a natural method which at the same time produces a natural looking decoration. The major downside is cost.
One way of keeping the cost down is to obtain so-called base rock from the dealer, strangely enough to form the base of the rock formation. Top quality live rock is then used to cover this base. The price though remains very noticeable. Another cost controlling method is to use a framework support. This framework must of course be marine suitable. The framework forms a support for the live rock and is not seen. The disadvantage is that there is less live rock so care has to be taken that the biological filtration is adequate. An advantage is that as there is less rock there is more seawater.
Another way of doing it is to use uncured rock, that is, rock that is obtained as soon as it arrives without any attention being given to it. It still costs of course but is much cheaper than cured live rock, perhaps two-thirds cheaper. This reduction in cost is because the rock has not been subjected to time-consuming attention. There isn’t any reason why the rock cannot be cured by the aquarist. It is essential that there is an adequate container for all the rock to be under seawater, this doesn’t have to be anything in particular but something strong enough, big enough and suitable for seawater, perhaps a large plastic container.
When a suitable container is found, it should be clean then filled about one third full with prepared seawater, the reason for the one third amount is for displacement. Some extra seawater should be available in case the rocks are not fully covered, any additional unused seawater will not be wasted as there is the aquarium to fill in due course (the seawater used to cure the rocks should not be used but disposed of). A heater is required also circulation pumps that will move the seawater quite vigorously around the rocks. The temperature should be set at the intended aquarium temperature, say 75 degrees F. Another piece of equipment that will be used is a protein skimmer, this can also be used in the curing process. If the marine aquarium (as yet empty) is owned along with the necessary equipment then skimmer, heater(s) and circulators are already available. If not, purchase ones that will be useable in the intended marine aquarium set-up.
Ok, so all is ready and the uncured live rock has arrived. It will now be ‘cured’. No it hasn’t a disease! In transit the rock is damp not wet so life is threatened or lost. This means that the dead organisms need to be removed and the required ones under threat allowed to hopefully recover. The rock can also have unwanted organisms which can be removed. The rock is placed in the container ensuring that the seawater covers it. The protein skimmer, heater(s) and circulators are activated. To fight any kind of unwanted algae growth it is best to cover the container with something to stop light entry. Then it’s a question of patience.
As time passes regularly check for evaporation and top up the seawater level (use fresh water, salt doesn’t evaporate). Regularly check the salinity and the temperature. Empty and clean the skimmer when required. Watch out for any obvious debris on or around the rocks plus any clearly dead organisms still attached. It is important to clear away this debris or recovering organisms could be effected and begin to die. After a good few days begin to carry out ammonia and nitrite checks. These could be high to start with but should slowly reduce. When ammonia and nitrite are not present and the tests have shown clear for a few days still check for unwanted organisms and debris.
If the seawater tests continue to show as clear (if a nitrate test is done this could/will be high) then the main aquarium can be prepared for the rocks. There should be a sufficient amount of freshly prepared heated seawater, clearly the seawater used for curing should not be used, this will be thrown away. The freshly prepared seawater should be at the same temperature as the curing seawater. Transfer any equipment that has been used, cleaning it as required. Fill the aquarium one third full with the new seawater and then begin the rock transfer. It may be possible to select rocks to produce the formation required but alterations can be done later. When rocks are lifted out of the curing container allow them to drip for a short while, until the drip is very slow or gone. A final check for unwanted life or rubbish is a good idea. When the rocks are in the aquarium ensure all the equipment is running properly. At this point lighting is not necessary but of course should be available. Tests of the seawater, ammonia, nitrite and nitrate, should be done and if they are stable and correct then the next stage, slowly populating the aquarium, can begin. Testing must continue. Patience is important from the curing stage right through to populating the display aquarium.
The procedure for saving money with live rock could seem a little difficult but it isn’t. It is time consuming but worth it at the end. There are other ways of saving money and obtaining live rock, for example buying dry (that is suitable rock that is not marine sourced) and using it in the aquarium straight away. This rock runs alongside two canister filters (each half the size required for provision of full bacterial support. Over many months the rock is populated with the required bacteria.) After a very long period the canisters are removed one at a time with seawater tests being regularly done. The canisters can of course be used for other purposes.
It could be that the aquarist grits his/her teeth and buys suitable ready rock in the first place. Fair enough. However, it can be very satisfying preparing rock as described and at the same time saving a fair amount of money.