Can You Add Too Many Corals at Once To a Reef Tank?

Are you nervous about the number of corals you should add to your new reef tank? If so, then there is no need to be. Back then, I had the same trouble and was ramming my head regarding how many I should be adding into my reef tank? Should I start with 2-3 corals at once or go all the way to about say 20-30 corals?

You can add up to 40 corals at once. Corals don’t add much pollution to your tank and therefore have a low bio-load. Monitor the water parameters when adding a lot of coral at once: it should remain stable. It’s better to add coral in smaller batches to see how they respond to the new conditions.

Many beginner aquarists might choose to add too many corals without attending to the water parameters and tank conditions. There is a lot to consider when becoming sure about the number of corals that can be added at once. Simply addressing the water parameters won’t make it any simpler for you; there is more to it

Effect of bio-load on coral addition

As discussed earlier, other than water parameters, the direct increase in the bio-load proposed by coral addition is a necessary factor to consider. Corals produce less bio-load than other aquatic creatures such as fish, which means they can be added in large numbers. It’s less, but it’s not neglectable and therefore is something that you should keep in mind.

Bio-load is the waste produced by livestock; fish and plants produce a ton of waste, so nitrogen cycling is required here. However, for corals it’s not; that is why you can add them right in without worrying about nitrogen cycling. But algae bloom and the water conditions are something that you should take seriously. Not every parameter that you used to work in the past with fish is going to be the same in the case of corals.

Is nitrogen cycling crucial before adding corals?

Nitrogen cycling is a process in which the nitrogen levels present in your tank are managed by being broken into less complex substances such as nitrites and nitrates. The nitrates and nitrites follow a re-uptake where plants use these to produce food, thus bringing these substances into some use. It is a complete cycle that keeps the plants and fish’ vitality in check while helping you manage the overall nitrogen levels within your tank’s ecosystem.

As described earlier, the fish and plants produce a lot of waste (bio-load), which is mostly nitrogen; that is why the nitrogen cycle becomes an essential factor to consider in their case.  

As a matter of fact, you can’t add more fish to an already crowded tank until you don’t buy a new tank that is bigger or perform effective nitrogen cycling first. In the case of fish and aquatic plants, it is a necessity, while in the case of corals, not so much because their bio-load (waste) is only minute and easily manageable without nitrogen cycling.

How long should you typically wait after cycling to add corals?

There is no typical timeline for adding corals into the reef tank once nitrogen cycling has been completed. You can very well check and verify that all the water parameters (pH, phosphate, and ammonia levels) are stable, and if these are, then you can add corals at the spot. But to be sure, normally, a 30-day timeline is given to the beginners to avoid any complications when it comes to the imbalance of chemicals in the water.

After nitrogen cycling is done, the algae bloom has disappeared, and water parameters are thriving; you can add corals in bulk about 30-40 frags at a time. After the first batch gets acclimated, you should wait for water parameters to get back in sync with the recommended values before adding a new batch. Typical water parameters for corals are as follows;

  • pH: 8-12
  • Ammonia: 0 ppm
  • Calcium: 400 ppm
  • Nitrate: 30-40 ppm
  • Nitrite: close to zero
  • Phosphate: <0.2 ppm
  • Temperature: 73-84 Fahrenheit

Do algae blooms hinder coral addition?

Algae bloom is referred to the extensive growth of algae within the reef tank soon after it is filled with water. The water that is being added to the tank is either tap water or non-purified water that has some sort of algae present in it. The result is a massive growth of algae covering every inch of your tank, known as algae bloom.

It is another critical factor that can verily affect corals’ addition to your reef tank. If there is too much algae bloom, then you can’t add any of your corals. You would first have to get the Algae Bloom in check before adding even a single frag. The very reason is that algae would start growing around your corals when you add them, thus hindering their growth.

How do algae bloom affect coral’s growth?

Too many algae can become the source of releasing the gigantic amount of nutrients known as the dissolved organic carbon. It is something that microbes eat and flourish around. Too much availability of these nutrients can become the reason for higher levels of potentially harmful microbes.

These microbes can introduce various diseases to corals or depleting the amount of oxygen available to them, thus affecting coral’s growth. As some corals die off, the present algae start using nutrients and minerals made available as a result of coral’s decay to flourish and grow unexpectedly. It adds to the overall mortality for corals; thus, algae bloom should be tackled first and foremost if your corals are to flourish.  

How to control algae blooms?

Normally for a 55 gallons tank, you can add about 30-40 coral frags at the same time, and these will flourish unquestionably, but it is a different case with algae blooms. When preparing your reef tank for coral addition, algae blooms are the common enemy you have to tackle.

In fact, you have to clear out all of the algae bloom if you wish to add corals to your reef tank. You can ignore nitrogen cycling as described earlier for adding corals, but you can’t do the same with algae blooms. It can take anywhere between 48-72 hours to address the green bloom issue, but at the end of the day, it depends on the severity and overall quantity of algae bloom growing in your aquarium.

Following are some of the ways you can get rid of algae bloom;

  • Installing a UV water sterilizer
  • Reducing the blue spectrum of tank’s lighting to hinder algae’s photosynthesis
  • Managing nitrogen levels through nitrogen cycling
  • To clear some of the algae manually.
  • Lowering the phosphate levels of the water

Tips for maintaining corals in a reef tank

There is hardly any coral or livestock, for that matter, that comes with unlimited endurance. Sooner or later, these are going to perish; that is why it is essential to make sure that your reef tank is properly maintained on a consistent basis to ensure that your corals can have a chance at prolonged life;

Lighting is important

Lighting is an essential factor when it comes to your coral’s growth and the beautiful color that will appear on their bodies with time. LED technology has revolutionized the world for good, and everyone is trying to get their hands on this brightly colored and cost-effective alternative, so why shouldn’t you? Getting an LED lamp that comes with the light intensity control switch is the best thing that you can get for corals right now.

Good flow is necessary.

You need to ensure that the nitrates and phosphate build up can be reduced as neatly as possible, so having a sound water flow system in place is necessary. It helps remove the detritus that will start building up at the bottom, which contains a strong amount of nitrates and phosphates.

On the other hand, good circulation ensures that your corals are getting enough nutrients required for their optimum growth.

Patience is the key

It might seem irrelevant but considering how difficult this job can be at times, having patience is the key here. From regulating water parameters to feeding corals and from adjusting the light intensity to removing algae bloom, the whole process requires so much patience on your end. If you can’t be patient, then this hobby is not for you.

Final Thoughts

Adding corals to a reef tank is not a problem as you can continue to add as many as you want because they have less bio-load than other livestock. The real problem is adjusting various parameters that accompany this step, and this is where you can either make or break it. Be mentally prepared about all the work that you would have to put into it and keep learning so improvements can make their way into this hobby for you.      

Bart Sprenkels


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