A few months ago my tank was spiraling downhill pretty quickly, as I was mysteriously losing a large number of corals, including many LPS colonies and SPS frags. I probably lost 50% of my corals and the ones remaining were not looking good. Common symptoms among the SPS were burnt tips, recession and expulsion of some sort of slime. Polyps on the LPS were retracted and on some the skin was shedding. Things were going to hell in a handbasket very quickly.

 

My parameters seemed ok according to my test kits but something was going on that I had never seen before. I needed to take a closer look so I ordered some Triton ICP tests to get a detailed look at all of the tank’s elements.

Using Triton to Dissect the Problem

I had done a Triton test a few months before in September when the tank was doing well so that would serve as a good benchmark versus results during the height of the near-crash, which was this past December. Here is what stood out when comparing results:

  • Phosphate dropped from 0.01795608 to 0.0065331 ppm, a 64% decline.
  • Lithium climbed from 713 to 929 ug/l, a 30% increase.

The low phosphate was concerning but what about the high lithium? Some industry experts claim high lithium levels are not detrimental to corals in a reef tank but in my view it was a small red flag.


Nonetheless, I decided to act fast with the hope of quickly turning the tank around. I ended up switching from one salt brand to another and changed out 50% of the water over three days. I also doubled the dose of trace elements I was using.

Tank Rebounds

Soon after the tank began to stabilize and the corals started to rebound. Yes! The tank continued to do well over the next several weeks and I decided to order another Triton test to see how things compared to the other two tests. What did I learn from the test after the rebound versus the test during the near-crash?

  • Phosphate increased from 0.0065331 to 0.01146888 ppm, a 76% jump (I started dosing phosphate and continued to do so to further increase levels).
  • Lithium declined by 18% from 929 to 766 ug/l.

Based on results from the three tests, I would have to conclude that very low phosphate levels had something to do with the near-crash. Perhaps elevated magnesium was an issue as well, with levels coming down from 1538 mg/l during the near-crash to 1434 mg/l during the rebound. I am going to assume the large water changes helped to mitigate the concentration of magnesium and maybe the switch to the new salt played a role as well.

 

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Was the near-crash due to a combination of low nutrients (phosphate and nitrate) and high alkalinity? Burnt tips on SPS is a sign of this as the tissue may not be able to keep up with skeletal growth, leaving the thin tissue prone to burning by high intensity light. According to my Salifert test kits, the alkalinity was 8.9 dkh before and during the near-crash while nitrates were 2.5 ppm during both periods. During the rebound the alkalinity climbed to 9.9 dkh and the nitrates were 5 ppm. I am just not sure the alkalinity was high enough during the near-crash to be an issue, but my nutrients did climb during the rebound.

 

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What about lithium? My lithium level after the rebound was actually a bit higher then the level before the near-crash so I don’t think that was a factor.

 

Do you have a different theory on what happened? All the data is here so have at it and let me know what you think!

 

 

If you are looking for additional insights and information, please explore my many other reef tank and SPS related articles as well as my book, A ReefBum’s Guide To Keeping an SPS Reef Tank: A Blueprint For Success. And you can see all of my reef tank videos online now as well as my Live HD Webcam.

 

Happy reef keeping!