Cleaning tank of limescale.

Question
I have a two year old, established, 29-gallon, freshwater tank that has some serious limescale build-up.  I have read that it can be cleaned with a simple paste of baking soda and water.  The problem is I have three black-neon tetras left in the tank, and I was wondering where I could keep them until the tank is clean, because I do not have a quarantine tank.  I would also like know how long it would be until I could return them to the tank after cleaning it with the baking soda-water solution.
                                               -Kyle


Answer
Hi Kyle;

If you have a clean bucket (fish only - no soap or cleaners ever used in it) or very large jar to put them in with an airstone that's a good place to keep them. Keep it in a spot where it can stay 75f. I really can't recommend totally emptying your tank though. That's what you would have to do in order to get rid of the used baking soda and it will kill the beneficial bacteria in your aquarium. The tank will have to go through a break-in period and it's very hard on the fish. But there is another option;

If you have a glass tank (not plastic or plexiglass) and the limescale is on the inside of glass itself, just use a single edged razor blade. Just don't cut into the sealant. Just lower the water level, do the scraping VERY carefully and then refill. The stuff that comes off your tank will fall in the water but won't hurt the fish at all. I've been doing it for years. You could make a water change right after if you want. Or, just hold a clean wet paper towel under it and wipe as you go. I like to wet the area first so there isn't a dry scraping sound. It's like fingernails on the chalkboard. Yikes! You can even get a holder for the blade at hardware stores so it's easier and safer to use. They are just a simple razor scraper with refills. I find them in the painting aisle and are used to remove traces of paint on windows and stuff. Pretty safe, clean, effective  and no chemicals!

At Your Service;
Chris Robbins