Zoanthid Problem- Why?

okay so all this talk of iodine, is it the same stuff I clean my kids cuts with from the first aid kit?

I agree with Ben. In fact, from all that you have said about the conditions in both tanks, I am almost 100% certain of it. In the large tank try to remove the Zoanthid colonies if possible, but definitely in the Nano remove the colonies and treat them as explained next.

I would carefully remove the Zoanthid colonies by lifting them out in a container. This is to avoid letting the pests drain off if the Zoanthids were to be removed bare from the water. Under running tap water use an old soft bristled toothbrush to vigorously brush every inch of the Zoanthids and the rock surrounding them.  Don't worry, they like a good brushing. Do this quickly, taking no longer than a few minutes under tap water. Then, to be sure I would then dip them in a new saltwater and iodine dip (no, not the Iodine from a First Aid Kit) for a few minutes before returning them to the tank.

FYI, the Caulerpa is not the problem. That macroalgae does not remove enough elements from the water to cause coral any problem. On the contrary, coral and algae live better together than apart.

ORP does not indicate a visually dirty tank. In actual fact, some pretty "dirty" looking tanks have good ORP levels. Let me explain.
ORP stands for Oxidation Reduction Potential. It is an indicator of the ability of the tank to decompose and oxidize, or burn up, organic matter. Good water parameters create better microscopic life in the tank, including algae and bacteria. More microscopic life in the tank results in a better ORP reading because organic matter is being decomposed better.

ORP can be mechanically increased by using Ozone (O3), to physically burn up the organic matter. This artificial burning creates less need for bacteria to do the job. Oxygen normally exists in the air as O2. O3 is the three Oxygen molecule produced by lightening during a thunderstorm. The best way to use O3 in a reef aquarium is to generate a small amount and add it to a Skimmers air intake.

Most Ozone Generators have the ability to adjust the amount of O3 produced. The best way to set the O3 is to start at a low level and watch the tank for 4-7 days to see if the water is clearer and coral look a little brighter because the water is clearer. Sometimes, but not always, coral polyps may extend further with O3 use.

One of the great fallacies about O3 is that it should never be used without a controller. In truth, the use of a "controller" should be considered only as a safety measure, used to turn off the O3 if somehow the adjustment knob was accidentally bumped and too much is being added to the skimmer air. (Placing the O3 Generator out of the way or placing duct tape to hold the knob in place is the simple answer. ) A controller should never be used to turn on and off an O3 Generator that has been set at full production. This repeated on and off of a full "flame" of O3 is very damaging even lethal to a reef aquarium. Rather, the hobbyist can keep the O3 set at a low level and never need a controller.

Maybe that's too much information for some, but I hope it's helpful to at least a few of you.


Edited by Mark Peterson - January 15 2011 at 9:20am