Dealing with high phosphates in reef aquariums is something that every marine hobbyist will have to address. There are many ways to handle high phosphates such as frequent water changes, GFO, Chateo algae in the sump, and my favorite to date is algae scrubbers (read about algae Scrubbers on Corallore). However this article is not specifically about how to lower your high phosphates since that has been discussed many times through forums and articles on the internet and books. This article goes over the important steps you need to take to protect your reef inhabitants while you have high phosphates so they do not die.
Whenever you realize you have high phosphates in your aquarium I think the first and most obvious step is to start with a large water change. Get some clean water circulating through your system. The next step I recommend is to dial in your protein skimmer to skim more heavy or “wet”. It’s possible if you have high phosphates you weren’t skimming enough to begin with.
The third step and one I actually recently learned of myself is adjusting your lighting period during high phosphates. It was pointed out to me in another forum and using his advice my SPS made a very rapid recovery in just a few weeks instead of the few months I had anticipated.
If you are a frequent reader of my posts you will know that I had recently added an algae scrubber to a heavily fed reef tank. Heavily feeding the tank causes high nitrates and high phosphates. I do not want to spend a lot of money on constant water changes so I installed a large algae scrubber. An unexpected side effect of the algae scrubber was that as algae was transferred from the tank to the scrubber it made my phosphates spike for a short time. I attribute this to a quick die off of tank algae releasing phosphates into the water.
Here is a picture of a green Montipora cap one month before the high phosphates in the reef aquarium.
Once the high phosphate spike was underway the Green Montipora Cap turned a dark brown. This was not a one month transition to this color, it happened practically over night, i just didn’t have a picture from the previous day.
Having been a marine hobbyist for many years I have experienced phosphate spikes before and generally corals are sadly lost and the ones which survive take a few months to fully bounce back to their former beauty.
The browning of this particular Montipora was almost an overnight transition which was incredibly fast. This indicated to me that it wasn’t the normal browning you get from low light or the slow browning you get from to many nutrients in water, something else was going on. Which lead me to forums to maybe see if there was something I had missed, that’s when I had gotten this piece of advice from a fellow reefer and I cannot thank him enough so I thought I would pass the tip along.
“P04 causes a coral to become photo-inhibited, which in turns makes it more sensitive to light and prone to bleaching, browning, and dying under normal reef lighting conditions. You might consider either shortening the photoperiod a bit further, or if possible, lower the intensity until you get your phosphates down.”
I adjusted my lighting schedule to be six hours and less intense instead of the 9 hours at one hundred percent. My algae scrubber, skimmer, and water changes quickly had the spike under control and to my surprise the coral color immediately started to change back to green. Had I kept the lighting period and intensity the same the corals would of continued to struggle for longer causing the recovery to be slower. Over the course of two weeks I gradually ramped the lighting period back to what it previously was and no corals were lost.
Less than one month later the montipora cap has returned to its former color and everything is fine.
To recap the steps so far I have found most important to take during a high phosphate spike:
- Frequent and large water changes
- Dial in your protein skimmer to skim wetter.
- Dial down your lighting period during the phosphate spike.
Hopefully using these steps you will not experience any coral loss and your recovery period will be short and you will be back to enjoying your beautiful reef as fast as possible!