Old Wives' Tales
These are things you will encounter during your time in the saltwater hobby I've found to be half-right, misleading or just plain wrong. Read on and you will see what I mean.
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The idea you have to pump water in and out of your tank at 10 times the volume of your tank isn't necessary. I have been waiting for years for someone to tell me why. The biggest problem is the size of your overflow pipe. A 1 inch hose handles roughly 600 GPH. If you a 1800 GPH pump for a 180 gallon tank you have to use three 1” overflows or one 4” overflow. Noise is another problem when you have more flow than a pipe can handle. The water level will rise and then start to siphon causing a loud, sucking noise. Using various anti-noise devices reduces noise but it's like putting a band-aid on a broken leg.
To calculate approximate flow ratios is easy. Take the diameter of the 2 pipes you want to compare - let's use 1” pipe and 2” pipe. Multiply the diameter by itself for each pipe. 1 X 1 = 1 AND 2 X 2 = 4. The ratio then is 1 to 4. A 2” pipe handles 4 times the water of a 1” pipe.
COMPARISON CHART AGAINST A 1” OVERFLOW GRAVITY FEED
PIPE RELATIVE FLOW
DIA. RATIO BY GRAVITY IN GPH
2” 2 X 2= 4 2400
1.5” 1.5 X 1.5= 2.25 1350
1” 1 X 1=1 600
3/4” .75 X .75 = .56 335
1/2” .5 X .5 = .25 150
The average coral tank needs low flow, SPS or Stony takes can handle super flow from powerheads, closed loop systems, and large return pumps.
WATTS PER GALLON really is misleading. The depth of the tank is most important followed by the requirement of the tanks inhabitants. (corals). If you put 500 watts over a low wide tank and the same 500 watts over a very tall tank, you get 2 very different light amounts at the bottom of the tank where it counts.
POUNDS PER GALLON OF LIVE ROCK might work if only one type of rock were available. Since live rock comes from many locations around the world, you get different density and different forms of rock. Tonga rock is extremely dense, the total volume is quite small. You can get a Fiji rock that is very spacious and takes up a lot of total volume. You get much more for your money on the spacious, “lots of holes” rock even if it a few dollars more per pound. Landscape your tank the way you like it, not by some formula.
DEEP SAND BEDS DO NOT de-nitrate as you might think. When you add over 1 inch of sand to a tank, the well oxygenated water doesn't get to the lower sand. Anaerobic conditions begin (no oxygen). The ocean has literally 1 million little creatures per square meter churning up the REAL live sand. Your deep sand bed will never have these nor is there a way to introduce them. Read my page on plenums. (Aquarium Setups )
1 ANGEL PER TANK is one I disprove constantly in my holding tanks. My home aquarium started off many years ago with 13 different species of angels. All deaths were by natural causes. I don't recommend 2 of the same species when the possibility of 2 males being put together exists, they MIGHT fight. I guess the fish never read the Internet. SEE PHOTO BELOW
CLEAN UP CREW CRITTERS PER GALLON (crabs, snails, etc) are designed to empty your wallet. A clean up crew isn't needed until the 2 stages of tank cycling algae are gone (1st reddish brown then a very tiny green). These critters are scavengers - don't worry about feeding them. More “crew“ members starve or get eaten by other crew members who are bigger and hungrier than die naturally. 6 snails in a 100 gallon are enough. Arrow crabs are not very safe to have. They will kill and eat shrimp, crabs, small fish and other small things.
FEEDING ANEMONES SILVERSIDES and krill is a sure fire way to starve them and pollute your tank. Anemones don't have real stomachs, they secrete digestive juices. Very small to tiny pieces of food (brine) are much more easily digested. Anemones often grab enough food when the fish are fed to keep them well fed. Frozen brine and mysis shrimp work fine.
RAISING THE TEMPERATURE TO KILL ICK works only if the tank is empty of fish, inverts and corals. Ick has a 6-10 day life cycle that depends on temperature. Higher temperature speeds up the cycle. If no fish are present, the parasites have no where to attach and grow. They then start dying off. If critters are present they are stressed by the heat and suffer or die. If your tank has ick and is empty, raise temperature to 85 for 3 weeks. That should kill off most parasites. Remember they never really go away - it only takes one to start the infection again.
Remember that Garlic and Marine Max are good preventatives.
For those of you who use 100 micron filters.
Ick is approximately 300 microns and can be filtered out with 100 micron material (300 microns are 3 times bigger than 100 microns.)
INCHES OF FISH PER GALLONS OF WATER is a freshwater rule of thumb because you can crowd freshwater fish. Saltwater fish aren't as sociable and you choose fish that swim and fish that are bottom dwellers.
USING WATER FROM AN ESTABLISHED TANK TO START A NEW TANK doesn't do anything to speed the cycling of a new tank. If anything it is adding dirty water to clean, new system. The possibility of transferring unwanted pests, diseases, and/or chemicals and contaminants exists. DON'T DO IT.
RAISING COPOPODS IN YOU REFUGIUM to feed your tank isn't realistic because Pods would get ground up by the pump's impellor. The are not free swimming either and not likely to crawl into the intake.
LIVE ROCK doesn't need light to survive. Just saltwater.
IT IS NOT TRUE THAT PERCULA CLOWNS FROM THE OCEAN AND OCELLARIS OR FALSE PERCULAS ARE NOT. THEY ARE 2 DISTINCT SPECIES BOTH FROM THE OCEAN.
