Every reefer wants their acropora to thrive in their tanks, and making sure your corals get proper lighting plays a big part in their health and happiness!
Most acropora will do just fine with 200 to 300 PAR, but with a few specific types of acropora, they can take up to 750 PAR. Just remember to check the needs of your specific coral before adjusting anything!
Why PAR Is Important
If you're fairly new to keeping your own reef tank, or you're passing knowledge along, you should know why it’s important to provide your corals with the right amount of PAR.
PAR, which stands for Photosynthetic Available Radiation, is the exact amount of light, or the exact intensity of the light that your corals should receive to keep them at their best.
Your PAR levels are important to know and monitor because it makes it easier to add new corals to your tank, and it makes it easier to compare light fixtures so you can find the best fit for your reef.
How to tell if your acropora are receiving enough PAR
If you’re unsure about the required amount of PAR for your acropora and want to make sure they’re getting everything they need, there is one sure-fire way to tell: their coloring.
If your corals are receiving enough PAR, you’ll observe healthy growth and vibrant coloring.
But on the other hand, if they’re not receiving enough light, they’ll begin to turn dark or brown.
How to tell if your acropora are receiving too much PAR
Too much of a good thing can be harmful, and it’s crucial to your acropora’s overall health that you look out for signs that your acropora are receiving too much light.
Your coral will begin to look bleached, and the longer it’s overexposed to light, the longer it will take for its healthy color to return.
Why does PAR affect color?
Lighting directly affects the coloring in your acropora because of little single-celled dinoflagellates called zooxanthellae.
Zooxanthellae can provide what your corals need to be able to grow and reproduce when they receive enough sunlight (and light in general) and other nutrients.
These photosynthetic organisms live in all sorts of different types of corals, and they play a big part in every reef tank.
When your acropora is getting too little light, the zooxanthellae, which is typically brown, will begin to seek out more nutrients and build up on the surface of your corals, giving it its brown color.
But when your corals are receiving too much light, your acropora will begin to expel zooxanthellae, which results in your acropora becoming more and more pale until it looks bleached.
In short, lighting affects your corals’ zooxanthellae, which affects the overall color!
However, your corals and their coloring can be affected by more than just lighting. The water’s temperature and even low nutrients can be contributing factors, with lighting being the easiest to identify and control.
That’s why it’s so important to measure PAR and make sure your tank is properly monitored.
Measuring PAR
To properly measure your PAR, it’s best to use a meter specifically designed to keep a close eye on your aquarium’s lighting.
Once you’ve figured out what works for your corals, you’ll want to keep the overall lighting consistent throughout the tank, and make sure your acropora are all at depth levels that allow them to receive enough lighting!
When measuring your reef tank’s PAR, you’ll want to take into consideration the needs of each coral, the overall size of your tank, and your light fixture’s lens and reflectors.
Just the FAQs About Your Tank
Because there’s so much to learn about PAR and the proper care of acropora, we’re sure that you have a few follow-up questions.
We’ll begin with the best tips for caring for acropora and the best depth for them!
What is the best depth for my acropora?
The best depth for your coral can depend on a few different factors. One of them being how much light that specific type of coral requires.
If your tank is too large, it can be difficult for certain types of corals to get the proper amount of light, so it’s a good rule of thumb to not have an aquarium any deeper than 24 inches for coral reef tanks. It’s also crucial for your acropora’s health that, when first introduced to their new home, their depth is equal or close to that of their original tank.
PAR and depth go hand in hand, so it’s important to check the parameters of your specific acropora species before placing them in your reef. Overall, it’s best to simply keep an eye on your corals’ and their coloring to see where they thrive.
Should I try to imitate (or use) natural light?
When trying to decide on LEDs, you might be wondering if you should attempt to imitate natural light, or even use the sun. Is it better to recreate your acropora’s natural habitat or stick to what they’re used to?
We would recommend caution when experimenting with natural sunlight. Because the sun’s rays can be so intense, it can be very easy for your acropora to be overexposed, and it can throw their coloring off for long periods of time. Remember that not all acros occur naturally close to the surface. Many actually occur in deeper water up to 60 meters or 200 feet deep.
It’s best to find what works for your tank and stick with it. Once your coral is used to certain PAR levels, it’s best to only make small adjustments as you see fit.
Keeping Care on PAR
Taking the best possible care of your tank is easy once you’ve gotten the hang of proper coral placement and checking your tank’s PAR regularly.
We hope that this guide to how much PAR for acropora you need has been a big help, and that your acros are vibrant and thriving!
How are your acropora doing? Do you have any tips of your own that you’d like to share? Leave a comment and let us know -- we always love hearing from fellow reef-keepers!
