Larry Lunsford

It seems that I'm destined to be a magnet for chlorine problems. In the past I've written about my experiences with chlorine surges (20ppm - 40ppm while in Virginia, and levels fluctuating between 1ppm and 3ppm here in Littleton). The most recent surge I've seen occurred at our last Koi show at Ocean Journey.

At our 2001 Koi Show, we had the local fire department out to fill our tanks from a fire hydrant. They got all our tanks (total volume around 10,000 gallons) filled in about two hours. After all the tanks were full, I dosed each tank with dechlor (sodium thiosulfate). I then started testing all the tanks for chlorine. The first few tested negative - the normal dose of dechlor was doing its job.

Part way through testing the tanks, I suddenly started to get positive tests for chlorine. I double checked the tanks to be sure I wasn't mistaken - I was not. Some time in the middle of filling the tanks (just a two hour window), the chlorine level jumped by about 2ppm (from around 1ppm to around 3ppm). Had I not been so paranoid about testing for chlorine, we could have had a major problem. As it was, I just dosed with more dechlor and everything was fine.

The moral to this story is: you never know what's going to come out of your hose or when it will take a drastic change for the worse. I've tested for chlorine in several places and the only consistent thing I've found is that the chlorine level is never consistent. Protect your Koi by doing these two things: quarantine and test. Quarantine new water before introducing it into the main pond. You can do this by turning off your pumps and doing water changes in an upper pond section (that's free of Koi) or in a settling chamber (don't chlorinate your biofilter) or by using a separate tank, kiddy pool, 55 gallon drum, trash cans, etc. While your water is in quarantine, test it for chlorine. I use the La Motte test kit (available from Aquatic Eco Systems - part # LM680). Treat with dechlor as necessary. Don't release your quarantined water until it tests at 0.0 for chlorine.

Koi