pH in basic terms
Written by Dr Johnson
Simple drop type test with Bromthymol Blue
Stay above pH 7.0 for best results with Koi
pH can "crash" to 5.5 overnight due to fish, plant and bacterial activity without
adequate buffering of water - fatalities result.
Baking Soda is a good buffer. Check Total Alkalinity before its use, though.
(Use one teaspoon per ten gallons if the TA <100)
pH is a measurement of the free hydrogen ions in the system. pH is
measured on a scale of 1 to 14, but the pH required for life lies between 5.5
and 8.5. Individual species will have varying demands as far as pH.
Ignorance of the requirements of each species will result in the death of the
animal in question.
pH impacts fish in several ways.
First, if the pH is too low, a condition within the fish called "Acidosis" results.
Symptoms are anorexia, and then production of excess slime, isolation, and
resting on the bottom, finally, streaking of the fins, and death will occur. If the
pH is too high, the fish will produce excess slime, and will gasp at the
surface. Losses can be major. "Alkalosis" is hard to reverse once it occurs.
On the other hand, Acidosis is rapidly corrected once the pH is brought up to
a suitable range.
IMPORTANT: pH contributes to the toxicity of Ammonia.
At higher pH values, ammonia is more toxic.
Below pH 7.2 most Ammonia is ionized to "Ammonium" and is far less toxic.
PondCrisis.com: If you have a koi, pond or fish problem, this site takes you
through twenty easy questions and at the end you know what you need to fix
in your pond to create restored Koi health.
This has relevance if you are considering raising the pH in a system with
accumulating ammonias. There is a routine, inexpensive test that measures
pH, and compares the result to a color chart for the diagnosis. pH is prone to
"fall" in un-buffered systems, and can fall precipitously due to Oxygen
consumption, accumulation of Carbon dioxide, decay of fish and other
wastes, and the normal activity of nitrifying bacteria which reduce Ammonia
to Nitrite. "Crashes" from a normal pH all the way down to pH 5.5 can occur
overnight. At 5.5 the filter bacteria that may have contributed to the crash will
shut down, preventing the crash from dropping yet further. In systems where
the pH has been chemically stabilized by any of the commercial buffers, the
pH crash phenomena is not commonly seen. When "pH Crash" is observed,
bring up the pH **rapidly**, not slowly. Would you want to be removed from a
smoke-filled room rapidly or slowly?
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