Curing Live Rock – What Does it Mean and Should I Do It? - A Simple Explanation

Welcome to Simple Reefs. We are a very new website dedicated to showing you how you can have your very own simple marine aquarium without breaking the bank. This article forms part of our series on starting a simple, budget, marine aquarium or reef. Today we are talking about Curing Live Rock – What does it mean and should I do it?

We have been talking about live rock a lot, lately. Considering Simple Reefs is such a new website. I wanted to get the basics out of the way with first. Live Rock is a subject that comes up a lot in reef ownership. After all, live rock forms the basis of a reef while also providing your aquarium with a healthy and diverse bacterial filter to process ammonia from your fish’s waste.

If you need to catch up on this subject. You can check out our article on Live Rock, Dry Rock, and Life Rock for a simple explanation of the differences. You can also take a look at our article on how Dry Rock can save you tons of money. If you are undecided on how to start your rock scape but would like to see big savings.

Purchasing Live Rock

If you have decided to start your marine aquarium journey by filling your aquarium with Live Rock. Or, simply, need a piece of Live Rock to make your Dry Rock or Dry Sand come to life. Take a quick look at this guide on what to look for when purchasing Live Rock. It will help you identify a piece that is well aged and safe, thus eliminating some of the inherent risk present when buying Live Rock.

Now that we have purchased it, we have a decision to make. That decision will depend on a couple of factors. Namely, did we bring the Live Rock straight home from the fish shop or did we order the Live Rock online and have it shipped to us overnight? The answer to this question will help determine whether, or not, we are experiencing, what is known as, die off on the rocks.

What is Die Off?

Well, to put it simply, Live Rock is covered in living organics. Bacteria, small invertebrates, algae, molluscs, sponges, bivalves, feather dusters, etc. That’s what makes it “Live”. When we remove that rock from the water, those creatures are suddenly placed into a less than ideal situation. After all, they are salt water dwelling organisms and need to be submerged to carry on living. The second that rock is removed from the water, the clock starts ticking.

After a certain amount of time, the creatures will begin to die. Sponges first, then the invertebrates, then the surface bacteria. Keeping the rock wet will help prevent some of that dying but the process is inevitable. Especially considering it is impractical to ship a piece of rock across the country in a container of water. The best most places can do is to ship it inside of a wet bag with tissue paper, or something else, wrapped around it to keep the rock damp.

When we talk about die off, we are referring to the process of the organics on and within the rock dying off. Naturally, this die off is not a good thing. Anything that dies and is placed into your aquarium will begin to rot thanks to the salt water and the temperature.

When it rots, it will produce ammonia. Now, our aquariums are capable of handling certain amounts of ammonia when they are cycled. Even more so when they are mature. But that ammonia that comes from the die off can cause big problems. Overwhelming our biological filter and causing an accumulation of dangerous toxins in the water. This is where Curing our Live Rock comes in.

What Does Curing Live Rock Mean?

Curing Live Rock, simply, means that we are making the rock safe for use in our aquariums. I, suppose, you can look at the word “curing” in the same context as you would for hardening something. Curing the rock like you would a piece of polymer clay in the oven. We are hardening the rock to survive life in our aquarium. It’s not a perfect comparison but I think it works.

The curing process consists of placing the Live Rock into a bucket with saltwater, a heater, and a powerhead or wavemaker. The warm saltwater will cause the dead organics on the rock to rot away. The powerhead will keep the water moving to provide oxygen to the still living organics while, also, blowing dead and decaying matter off of the rocks.

We can also add a filter or skimmer to this process to remove the decaying matter from the water. Making it a cleaner operation. This task can, also, be accomplished, more affordably, by simply changing the dirty water and replacing it with freshly mixed, clean, saltwater every few days. The overall idea is that the organic matter dying on our rocks does so in a contained environment rather than in our aquarium.

In our aquarium, the ammonia would cause problems, in a bucket we can simply throw the dirty water away. We can let everything that is going to die on the rocks die off in a safe way. While, at the same time, allowing the still living organics on the rock to adapt to life in a far less mature aquarium. An environment that the bucket will replicate for us. This guide is missing a few details so click right here to check out our full article on How to Cure Live Rock.

How Long Does Curing Take?

This is one of those annoying “How long is a piece of string?” situations. The curing process can take a week or it can take a few months. It really depends on how mature the rock is, how many organics it played host to, how long it was out of water, and how well it adapts to the change in water parameters.

There’s no way to know, for sure, when starting, how long the curing process will take. We can increase the temperature of the water to around 25.5 – 26.5 degree Celsius (78-80 degrees Fahrenheit) to speed things up but that will only marginally impact the process.

If you had your rock in the post for a few days and, when it arrives, it is obviously very mature and smells pretty bad. Expect the process to take longer. If your rock was shipped over night and doesn’t smell too bad, it may take only a few days. If you just brought your rock back from the local fish shop or a fellow hobbyists house and it has only been out of water for a short while. You probably don’t need to cure it at all. Which brings us onto our next question.

Do I Need to Cure My Live Rock?

Again, this answer depends with the short answer being “not always”. There is a concrete, guaranteed, way to know whether it needs curing, or not, and a quick and dirty method. There is, also, advice that, I feel, conflicts between the USA and the UK and Europe. After all, I built Simple Reefs with the UK in mind as that is where I am from. The UK is, frequently, quite cold and that is going to lead to more die off during the shipping process. Meaning some of the advice for the USA doesn’t apply as much, here.

Some places suggest that you won’t need to cure your live rock if it was in shipping for less than four days. I wouldn’t buy into that, here, personally. Especially if it can from somewhere far away where transit time would be hard to determine. You should always check your live rock yourself.

The unscientific way to determine whether the Live Rock needs curing is to, first, take a good look at it. Are there any parts of the rock that contain soft black bits? If there are, the rock has die off. Does the rock have a lot of sponges? If so, they will likely be dead or will die when added to your aquarium.

Now open the bag, remove the rock. If it is bone dry, you may have a problem. While bacteria can survive deep in the rocks when it dries out. It’s hard to know, for sure, how long the rock has been dry for. If it has been dry for a decent amount of time, it could be completely dead.

Now give it a smell. Pretty gross but you will know, almost straight away, if there is die off. The smell of decaying matter is obvious. Your rock should smell like the seaside; nice and fresh. If it doesn’t, it will need curing. The more scientific way to tell is to place the rock into a bucket 3 quarters full with clean saltwater with a heater set to 25.5 – 26.5 degree Celsius (78-80 degrees Fahrenheit) and a powerhead or wavemaker to push water around. Leave the rock in the bucket for a day or two.

After a day or two, take a sample of the water and test it for ammonia. If your ammonia test comes back negative, or at a very negligible amount, the rock is fine. If, however, you have a positive test, you are going to want to move on to the process of curing the rock. Putting it in your aquarium now would be hazardous, at best, and catastrophic, at worst.

But My Live Rock Was Pre-Cured

That doesn’t matter, unfortunately. When buying Live Rock online pre-cured, or cured, simply means that it has gone through a curing process when the retailer received the rock. Meaning the die off that occurred between it being shipped from the supplier to the retailer has been dealt with. New die off will likely occur when it is shipped from the retailer to you. Meaning it may need curing again. Live Rock, often, needs curing at every step of the journey.

The major benefit of pre-cured live rock is that the die off might be significantly less and the rock will be in a far healthier condition. Imagine a scenario where the rock is shipped from the supplier, to the retailer, and then straight out to you with no stops in between. It could have been out of the water for weeks while making its journey. Meaning the die off will be tremendous. It’s much better to buy pre-cured but there is still a strong chance you will need to cure it again.

Should I Cure my Live Rock if Buying from a Local Fish Shop?

To be perfectly honest, as long as the fish shop has a decent setup and you are taking the rock straight home. I wouldn’t worry about curing it at all. It should be fine. There may be a small amount of die off from the difference in water parameters in your aquarium but it shouldn’t be too much for your aquarium to handle.

In fact, when starting a brand new aquarium, I find this die off to be quite useful. Proving ammonia to feed the still living bacteria on the rock and helping cycle your tank much faster. You may want to place the rock in a bucket purely to observe it. You don’t want to introduce pests like Aiptasia, Nudibranchs, or Flatworms, for example. But that is totally up to you.

My Aquarium Is New With No Residents!

Great, that means you can simply go ahead and whack the live rock into your aquarium. You can, effectively, cure the rock inside of your tank. Turn on your heater to get your water warm, turn on your filters and wavemakers or powerheads, place the rock in and we are good to go.

You may want to scrub any sponges off the rock before hand as they will likely die. If the tank is in a room with decent ambient lighting, keep the lights on your aquarium off all the time. If, however, you have the tank in a dark spot. Run your lights low for a few hours a day to give the stuff living on the rocks some light.

We don’t want to grow any nuisance algae in this early stage of the tank’s life which is why we avoid the lighting. Give the rock a few days, or so, in your aquarium and then begin testing the water for the presence of ammonia. When the ammonia disappears and you receive a clean test. Your rock is ready and you can add a resident to your aquarium.

It should be noted that live rock that has a lot of die off may result in your new aquarium’s cycling process stalling for a little while. That’s why it is important to test for ammonia. When done, it should bounce back well and you will be good to go.

How Do I Cure My Live Rock?

This is a subject for another article which I will be adding tomorrow. The process is fairly straight forward but it requires something that you are going to have to get used to in the marine aquarium owning hobby – patience. Remember, nothing good happens quickly in this hobby so get ready to do a lot of waiting. Thanks for reading.