Recent experience concerning Coral Vital and ORP

(*note: I do not wish to make claims about Coral vital, only speculation based on collected data. Also, the info presented regarding ORP is a basic undersatnding of oxidation-reduction potential as applied to reefkeeping. If you see anything in error, please disregard or let me know.)

ORP, or oxidation-reduction potential, is used by some reefkeepers as a relative measure of the relative purity of the water in their tanks. The potential gives an indication of the ability of the water to reduce, or oxidize, organic compunds in the system. The higher the potential, the less organics, and thus the cleaner the water in regards to dissolved organics. By the process of the nitrogen cycle, organics are mineralized into ammonia, and then nitrified to nitrite and nitrate. It has also been argued that dissolved organic forms of nitrogen and phosphate are detrimental to coralline algae and hard corals, while inorganic forms of nitrogen and phosphate are utilized by coralline algae and the symbiotic alge within photosynthetic corals. Also, organic compunds can be utilized by various micro and macro algae. Keeping organics low in a reef is a primary concern for most.

There are ways to increase the ORP readings in a reef. Use of a protien skimmer, GAC and adequate aeration of the water are somewhat natural ways to increase the redox potential. A way to increase redox even more is through the use of ozone, however I don't use ozone as it can be dangerous (to the reef and humans) if incorrectly used, and I don't need the added expense/maintenance/clutter of another gadget, an ozone generator. There are several factors which can also affect ORP readings such as temperature, Ph, and biological activity which I will not go into here. As a general guideline, ORP above 320mV is considered allright and above 350mV even better. Keep in mind though that absolute values are not always inportant with redox measurements. Instead, trends in the redox level should be observed to see if there is a rising or falling trend. a rapidly falling ORP reading can signal that something has died or something is decaying.

Now, my ORP readings have been fairly consistent and constant since I have had an ORP monitor. Trends usually go slowly down for a few days, then slowly up for a few days. Generally readings are 330mV-340mV during the day and peak at about 350mV in the morning. Recently, I decided to try a controversial product, Coral Vital, to see about it's claims about enhancing coralline algae growth and growth of corals in general. I have had good growth of SPS corals to begin with, but I decided to give it a try. Why not? I've tried alot of other things on my reef. The product claims to aid biological processes such as the reduction of organics by biological processes. For more info on Coral vital's claims, go to Mark Weiss page, http://petsforum.com/wwff/wwf001.html. One thing pointed out is that ORP reading may go down for a few minutes after the addition of Coral Vital and then come back to normal levels. Also stated is that ORP may begin to rise after continued use of Coral Vital. With this in mind, I proceeded to add my first dose of Coral vital to my reef. About ten minutes later I wandered past my ORP meter and, expecting to see a slightly lower reading, was shocked to see that the reading had gone from 335mV to about 355mV. I couldn't believe it! The level continued to rise for several hours and finally leveled off just above 380mV. I try to be careful about making hasty conclusions based on this. So far there are several possibilities to explain the change in ORP readings.

• 1. Coral Vital is causing an incorrect reading on my ORP monitor.
• 2. Coral vital actually raised the ORP of the water directly.
• 3. Coral vital increased the biological activity on organic compunds, thus reducing the amount of organics in the system, and raised the ORP reading.

Number three is what the product claims to do. However it seems an unlikely explanation in such a short amount of time. Had this increase occured over several days I could see it, but not in ten minutes. More likely is number 1 or 2, hopefully number 2 is the actuall explanation. I don't know if I will ever know for sure since I do not have a way to verify the ORP readings. Also, as pointed out previously, it is not the absolute value of the ORP reading, but the genaral trends, as well as the health of the inhabitants in my reef that are important.

The graph above shows Ph, ORP, and temp over time. ORP (red)values are divided by 10 and Ph(blue) is multiplied by 10. So an ORP value on the graph of 33 would actually be 330mV. The circled area shows the result of adding 5 ml of Coral vital. Within 1hr the ORP went from 335mV to 380mV and finally peaked at 390mV. The data was logged on a Neptune Systems Aqua Controller and the data downloaded to a PC and into Microsoft Excel. Samples are taken at 15 minute intervals.

Conclusion:

Having used Coral Vital only one day so far, there really is no conclusion yet. The makers of Coral Vital make some fantastic claims on its usefulness. In the news group rec.aquaria.marine.reefs, some substantiate the product's claims, while others say it is a waste of money. Hopefully I will find out in time whether it was worth the money spent.