Live Rocks!
It's not what you think!
By Tim Ryan
But a local entrepreneur's
humming a fine tune catering to
saltwater aquarium aficionados
Star-Bulletin\JERRY Linville is a pleasant, soft-spoken, modest man -- quite normal at first glance. But on weekends Linville rises early to leave his comfortable Nuuanu home for windward Oahu where he rows a small boat to the makai end of Heeia Fish pond. There he climbs into waist-deep water to observe, nurture and realign rocks. For hours.
Linville inspects them like some cherished offspring, gently brushing, or methodically scraping off something he doesn't think should be there. And when he finds a particularly good growth of sponges on one, Linville smiles like a proud pop.
"This is nice," he said on a recent drizzly morning at "the pond." "Look at that color, that growth."
Linville, through Pacific Aquaculture, raises big rocks, small rocks, lots and lots of rocks -- about 3.5 tons in stock right now. Technically speaking they are calcium carbonate skeletons off the ocean floor to be used in the most environmentally correct reef aquariums.
"These rocks," he says, "have been in the water for about 18 months. And they're ready.""Live rock" is growing in popularity for use in home aquariums. But the problem has been how to get them legally. In Hawaii it's against the law to remove live rock and coral from the ocean. Since Linville is leasing part of a privately owned fish pond for the live rock, he is not violating the law.
(The term "live rock" actually is a misnomer. The rock itself is not actually "alive" but contains lots of marine life inside and out.)
Using live rock in a marine aquarium immediately introduces numerous algae, bacteria and small invertebrates, all of which contribute to the overall water quality. It is, Linville says, "the most natural way" to filter aquarium water and if used properly can eliminate the need to use artificial, external filters.
"The organisms in the rock naturally biologically filters the (aquarium) water," Linville said. "It performs the same function as the organisms created in a wet-dry (filter) system."
Arrangement can influence the long-term success of a reef tank. Rock matters
Avoid placing live rocks into a pile like a brick wall and don't pile the rocks against the back wall of the aquarium. Such arrangements cut down on water circulation and cause detritus build-up
But you can't just plop down a few of Linville's rocks in your aquarium and throw away your filters to get that instant natural look.
Nature is a very difficult thing to duplicate. Reef tanks filled with multi-colored marine fish may be one of the most difficult environments to recreate and maintain because the slightest bit of pollution can have disastrous and expensive results.
Linville, a marine aquarist for a dozen years, started using live rock a couple years ago, not only for the filtration but the natural appearance.
"It's a lot better than just having bleached chunks of white coral sitting in the tank," he said. "This is the most stable (marine) aquarium I've ever had. When I had a fish-only tank with hundreds of dollars of filters I constantly had problems with fish dying."
Linville's tank now has only four fish but lots of live rock with various colored sponges and other invertebrates.
"There are lots of interesting things that grow on live rocks like pink, red, blue and orange sponges, and feather dusters," he said.
And ammonia, nitrate and phosphate are readily assimilated by algae and photosynthetic corals growing on and in the rock. Ammonia can also be quickly converted into nitrate by the bacteria on and in the rock. This nitrate can be either absorbed by the algae and corals, or it can be denitrified by bacteria in close proximity to the nitrate producing bacteria.
Live rock needs to cure and cycle, meaning it will need to go through a period during which some animal life on it dies, and bacteria start to grow in the porous areas of the rock. Curing live rock
The die off will create pollution in the tank in the form of ammonia and nitrite. As long this is present, no fish should be added to the tank because they'll be stressed and may die. Let the filtration system build up a bacterial level that neutralizes the ammonia and nitrite before you add fish. The first thing you should do when you get the live rocks home is rinse them in saltwater to remove any sand, debris and ammonia that's been released by the rock's inhabitants during transport. Then put the rock in a large container with strong circulating powerheads. Keep the lights off during the curing process because high intensity lighting can cause algae growth.
Stack the live rocks loosely inside the container to allow more water circulation. After about three weeks, the ammonia and nitrite levels should be close to zero or at zero. Now the live rocks are ready for the main display tank.
"In reef aquariums heavily loaded with fish or where overfeeding occurs, the production of nitrate may overcome the rock's ability to handle it and there'll be a build-up of nitrate in the system," he said.
That overload can cause at the very least stress on the fish and at the worse, a major die off.
The goal, Linville said, is to use just enough live rock so the aquarium system reaches a balanced state. The key to achieving balance is the condition of the live rock because the better the condition, the more stable the system. And that's where curing comes in. (See accompanying story.)
The rule of thumb is to use 1- to 2-pounds of live rock for each gallon of tank water.
Linville's limestone rocks range from softball size -- $3.50 a pound -- to 25 pounds -- $2.50 a pound.
So far customers of the 18-month-old business has come mostly from word of mouth from local pet stores. Too see Linville's live rocks up close, Borders Books Music & Cafe at Ward Center has two saltwater tanks filled with them.
Rock on!
