After the loss of a substantial amount of livestock, predominantly corals and all Acropora spp., due to a temperature spike at the very end of summer, it was time for a total reworking of my reef aquarium.

For a couple of years now I have been frustrated by the fact that the liverock making up the reef structure of my aquarium was covered in very prolific growing zoanthids. So much so that they were weeds, performing very well at out competing and smoothering/shading anything but the most aggressive corals. To add to this fact, the dominant species was not very attractive, being just a plain brown colour. Their numbers were way too high to use any control technique such as killing with an acid or base, which also isn't that easy when the victim spreaks over the rock and a single injection only kills a single polyp. Addionally, all that needs to be left alive from the treated zoanthid is a small amount attached to the rock, for this it can regenerate to return with avengence. The technique that was used to attempt to control their populations, with very limited success, was injection of small amounts of concentrated sodium hydroxide solution. Even when injected directly into the body of the polyps it would not kill them totally. Removing the infected rocks from the tank wasn't a viable option, as all of the major rocks making up the reef structure were covered to some extent. So what was really required was a total restocking of new liverock. Additionally, there was a small population of Anemonea sp., which were left unchecked for a short time and multiplied in several locations to a substantial population. So the wipe out was a perfect opportunity to do something about it. At least something positve would come of the very disheartening event.

Three boxes of liverock was ordered through Ian at Ivanhoe Aquarium. The sort of rock that I wanted was explicitly stated, with it having to be well shaped, with long pieces, branched, no boulders and the absence of zoanthids. No way did I wanted to go that way again! And these specifications were passed onto the collector. Couple of weeks or so later the rock arrived, it came direct from the airport to my house (since I live directly between the airport and Ivanhoe Aquarium) and it was exactly what I was looking for! Couldnt' have been happier with it and don't think it would have been possible to select a better range of shaped and sized rock myself from the collector's stock. A couple of various pieces are shown in photo 1. The rock was cycled in two linked 200 lt plastic tubs in the lounge room next to the tank, see photo 2. One tub contained all of the rock with three pumps for good circulation and the second a protein skimmer, two heaters and a pump to return the water to the first tub. It was left in those tubs for for 2 weeks for the die off to occur and until a destination was found for the old liverock. The die off and subsequent cycled was mild with the nitrite concentration dropping to zero before the end of the second week. This is predominately due to the absence of any major encrusting growns of corals, zoanthids and sponges covering the rock that may be stressed by the shipping and die off. The old rock found a new home in a large marine aquarium in a retirement home, which is being looked after by Storm. The old rock was moved out of the tank on Saturday morning. Then the next day, after things had settled down, the new liverock was moved in as just a pile at one end.

Photo 1: several pieces of the new liverock.

Photo 2: Cycling tubs for the new liverock in the lounge room.

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