Water Change Math, OTS
And Other Mismatches Between Tank and Source Water
This note assumes that you have read the note on what OTS is itself as well as the article on general Water Change Math, if you have not yet read those, you may want to scan them for background which may not be reviewed here.
Old Tank Syndrome, OTS {Click}
Water Change Math {Click}
When the water we want and plan to use does not match at all well with the existing tank conditions, if we do substantial changes we will subject the fish to sudden differences in the osmotic pressure of the water around them. This stress may be so severe that the fish suffer shock and may even die. They are adapted, hopefully and usually slowly, to the water that they are living in now. Too much change too fast is a system overload. This situation on the boards is commonly called “pH shock”, but it is not that, even though the pH may well be quite different. It is osmotic shock from the sudden change in TDS (total dissolved solids). TDS includes GH, KH, nitrate ion (NO3–), sodium chloride (Na+, Cl-), carbonates and bicarbonate, and all the other dissolved materials that we do not measure (potassium, sodium, sulfates, phosphates, organics, etc.).
Continue reading VII. Water Change Math, OTS