Temperature Swings:

If you are noticing that there are frequent swings of 5-10 degrees F, you need to implement a some sort of a control device. Best for that would be either a specifically designed temp controller, such as.. or a system controller (the likes of Reef Keeper or Profilux). In the winter months, many of us use heaters to keep up with the heat demands. Most heaters have a controller on their own, but can often fail with wear. Equivocally during summer months, your heat can rise and is in need to be cooled down. Many hobbyists employ fans, which are directed towards the surface of the water. Some use chillers, which require a lot of electricity to run. With a system controller unit, you can tell the heaters to turn on or off, with very small hysteresis(variance), and vice versa with your fans/chillers. Your temperature will be stabilized this way, and will not fluctuate during the day or night.

Salinity Swings:

The most important aspect of keeping stony corals is keeping the salinity levels at a steady mark. The best tool for keeping your salinity in check is to use a Auto Top Off (ATO) controller, which employs light sensors. These sensors tell the controller to dump more fresh RO water from your storage container. Now, if you want even more stability and piece of mind, allow the system controller (like a Profilux or RKE) to oversee the work being done by the ATO. In a case where the sensor fails, the system controller can override the ATO. It can pump or shut off a pump in an emergency within seconds. You can monitor your salinity digitally through a system controller, and set the desired levels based on your needs. Fluctuations will be a thing of the past.

Alkalinity Drops/Jumps:

The one thing that can be easily unnoticed is your alkalinity. If you have either a calcium reactor, kalkwasser reactor or a dosing unit, the rate of which you add alkalinity can change quickly. Either your effluent/intake line can get clogged, your kalk ratio is out of balance (high concentrations), your uptake of alkalinity changes by the livestock additions, etc. There isn’t a real way to control this, outside of using a steady dripping mechanism. The only way to sure know how to meet your system’s needs is to perform day-to-day ALK tests using a kit. Once you feel satisfied that you drip rate matches your uptake rate, the swings will be minimal and tolerable.

Avoid adding buffer in one shot, when trying to stabilize your pH (or ALK). A lot of hobbists combat the swings in pH by adding a bicarbonate product, such as the Baking Soda. The relationship between ALK and pH is positive, so if you enhance one parameter, the other will be enhanced as well. So be careful, as that could cause an STN event.

ULNS (Ultra Low Nutrient System):

Corals need nutrients to grow. They need light and they need food (zooplankton). So when you strip them from nutrients, you allow them to be in a very weak state. Only through additives, such as Amino Acids, Essential Elements (Potassium, Iron, Bromide, Strontium, etc, etc), are they allowed to gain their health back. So why even go that route? But not to digress, if you are subjected to this kind of environment, think about polluting your tank. You are probably thinking that this is a crazy idea, and one that is not shared by many. But, it is true. By adding Nitrogen (or Nitrates in this case), and Phosphorous (or Phosphates), you are giving what the corals need for growth. In small amounts, these elements are necessary in water. It is only through excess that we see overgrowth from algae. So feed your tank! Feed the fish, feed the corals. Add proteins, like fish eggs, silversides, mysis shrimp. Don’t thaw your frozen food for a time period. Let those phosphates into your water. Throttle down on your skimmer. Let the skimmate come our very thick.

Do this until you notice that your refugium macroalgae is starting to take off. You chaetomorpha should be in a growth spurt. That is a sign to slow down, as your nitrates are elevated. Some say in the meantime to dose Potassium and Bromide (ZeoVit sells K-Balance and B-Balance). They aid in restoring the health and color of corals. One indicator of low Potassium or Bromide is the loss of color in montiporas and blues/reds in acroporas. Look for this key when thinking about adding Potassium and Bromide. If you are unsure of adding this stuff, just complete a 25% water change, and that should take care of some of your needs.

But sometimes, you may be required to shorten your photoperiod, as the corals in this mode are more sensitive to light.. especially when they are irritated or depleted in nutrients. High light can cause an STN event, so be careful.

If you have your story to tell, or want to share, please make your comment below. We would love to hear from you, as I am sure many of your have encountered this problem. All of us can learn from your story.

While I do that, you can continue reading about STN and the real issues. I just hope you are not reading this without our part 1, as it will be confusing! Please catch up..

Slow Tissue Necrosis is something that all of SPS coral keepers do not want to encounter. Why? Because the cause is hard to decipher. It is only through your own analysis that you can catch the catalyst for this unfortunate event. And sometimes even that is not enough.

Case in point, the Ultra Low Nutrient Systems. They are designed to purify the water that your corals are grown in. But it is through additives, such as Amino Acids/ Proteins, Vitamins, Minerals that you get them to grow and display in pastel colors. Many hobbyists in Europe and now in USA employ this kind of method through the use of a Zeo or Ultralith product system. These systems require you to perform a daily routine in adding these supplements (which I mentioned before). In reality, this is a well executed marketing campaign that people bought into. You are fabricating an environment in which you are eliminating the necessary elements that your corals use to grow (such as Phosphates and Nitrates). Then you are required to purchase supplements to make them grow and color up. Finally, and this is the kicker (if you already didn’t know), you do have to maintain a regular water change schedule. How ironic?!

Your corals are basically walking the tightrope. Why? Consider this, and this is how this ties into STN, your corals are already deprived of everything that they need to grow on. If you miss adding your supplements, or if you overdose your supplements, you will be entering in the danger zone of possibly jump-starting a massive STN event. As well, the non-marketed ULNS, such as the Vodka/Sugar/Vitamin C  (Basic Carbon Sources) are also STN event creating sources. They allow your system to eliminate the Phosphates and Nitrates from your system, but through total elimination of these important elements that your corals will go into recession.

While doing some research on STN, I found this very intersting article that depicts what I have been talking about so far. It explains how food deprivation (such as in this case through PO4 and NO3), can cause coral death. Here is an excerpt:

There is good reason to suspect that the low lipid reserves and lowered immunity features precede the bleaching event rather than result from it, as one might suspect. Widespread outbreaks of infectious diseases and parasitic problems among (not bleached) corals have been another cause of serious concern to reef scientists, also starting only in recent years. And, as mentioned earlier, slowed growth of (not bleached) corals has actually been occurring in some “pristine” areas for decades. Therefore it is reasonable to suspect that some underlying factor has caused these changes and thereby weakened coral communities as a whole, and predisposed many corals now to “bleaching” under temperature stress. Food-deprivation is certainly consistent with the pattern of presenting symptoms (slowed growth, low lipid reserves, lowered immunity and reproduction, ultimate death).

 

In other words, no food for corals, no growth for corals and their untimely death.

Tomorrow, I will show you all what you can do to eliminate the possibilities of this event. So stay tuned!

So what is it? How do we get it? How do we stop it? How do we prevent it from happening again? These are all questions that need to be answered for us to be able to attack this problem rationally.

Throughout my years of SPS nurture, I have witnessed many accounts of STN that do result in some positive and much negative outcomes. There are those instances where things improve without notice, and sometimes, never even give a coral a chance to survive. The coral’s ‘skin’ recession begins at the base, and ends with the axial corallites (tips). So what is it really that makes the coral recede without warning? For now, the reasons are still ambiguous as there are many factors to consider. Some people claim that they see it begin with alkalinity swings. Some say that with temperature swings, you can get the same results. Currently, there is a new belief that in a low nutrient system (such as a Zeo, Ultralith), you can trigger an STN event. On that more later in part 2.

Here are some pictures of corals experiencing STN. Please note, these pictures are not for those of faint hearts:

While many accounts of STN can be attributed to rapid temperature fluctuations, or even alkalinity swings, none can be more perplexing as some witnessed in an ULN System (Ultra-Low Nutrient System). Stay tuned in tomorrow for my explanation on why ULN Systems are not good for your reef and what you can do to combat it.