I asked if the bottlers recorded HOW MUCH of those very essential minerals (try developing bones, muscles, properly working nervous systems without them). He surprised me by noted that they had to say what was put in their water but not how much. I guess that is what is called a proprietary trade secret for each company.

Let me reiterate. I am an aquarist, most certainly not a chemist. Not many chemical formulas get studied in history courses. ;)

Imagine my surprise when, out of curiosity I took a TDS meter to samples of a few bottles and jugs of locally sold "Drinking Water" and got wildly different readings on different products! A TDS meter measures almost all molecules other than the pure water. A hardness meter or test kit only measures a certain set of molecules (calcium, magnesium, iron and some others.) Interestingly sodium chloride doesn't show up on either pH or hardness meters. But boy does it show an influence upon TDS measurements!

Actually TDS meters are measuring microsiemens, a measure of conductivity. But for those of us with a gizmo labeled TDS meters, the readout is calibrated inside to give a number on the display. It is close enough for the purposes of gardeners and aquarists. (I got my Hanna TDS meter for about half the usual price from an orchid site on-line).

When moving guppies and other aquarium fish, we want to move fish into other tanks with water close to what they were used to. As a general principle, fish shouldn't be put into water of more than a degree difference in pH or into water a lot different in terms of hardness or total mineral content. A TDS meter has nothing to do with pH, but sure works well enough in other ways.

If a tank, which has just been left alone is measured with a TDS meter and the reading is a lot higher (say 500 PPM rather than 300 PPM) than it was a month before, it is time to get going with the partial water changes. A LOT of nitrates and other waste materials have gathered in there and the fish are in danger of nitrate poisoning!

As a general rule, we can move fish into water with slightly high temperatures (79 as opposed to 77F) or slightly high pH readings (7.9 as opposed to 7.5) or somewhat higher hardness or TDS. It stresses the fish more to go the other way, especially with temperature and then an Ick epidemic breaks out!

A dramatic example of a horrendous sudden change happened when a female killifish (silly girl) jumped out of her tank and into a barrel of RO water, which has virtually no hardness and almost no free oxygen. She was dead when I found her. A postmortem was not done, I do not know if she suffocated from a lack of oxygen or because the sudden osmotic pressure change of the water caused her gills to gradually burst. But I would not wish that fate on any creature!

The first water sample I tested was from an inexpensively priced gallon of "Drinking Water" from a discount grocery store. I was dumbfounded when it measured zero PPM on the meter! I took another cheap (69 or 79 cent) gallon of "Drinking Water" purchased and measured a sample. It measured 1 PPM.

A closer look at their labels indicated that the water in one case was purified by Reverse Osmosis. In the other case it was purified by Reverse Osmosis or Distillation. That is much the same as (and actually more pure than) the stuff coming out of my home RO unit! It is great for topping off winter evaporation in an aquarium, watering house plants, ironing clothing, or gradually lowering the mineral content in an aquarium so that tetras or some other "difficult" rain forest fish will begin to lay viable eggs.

But that water can be very dangerous if just added to an aquarium. While older men (vulnerable to stones in their urinary system) might be well advised to drink some RO water, it could be suicidal for athletes or people working in the summer heat to drink. Those people need the minerals in order to sweat and keep a consistent body temperature. A few years ago a college football player in this area collapsed after practice. His body temperature was rising rapidly. (At above 104 F proteins begin to break down.) They were unable to revive him and tragically he died.

While it is probably less dangerous, people with calcium deficiencies on their skeletal structure or osteoporosis or the potential for things of that sort don't need to drink those either. And they really don't need to make coffee with those waters. ;)

I'm no more a medical person than a chemist, but a letter may go out to these companies expressing my concern. I'm not interested in a lawsuit (not a lawyer either) but the potential for people getting hurt is there.

That water is just the opposite of these energy drinks, which have entirely too much stuff (a nice way of saying crap) in them.

A couple of other more expensive drinking waters were sampled. One brand name measured about 50 PPM and another associated with a grocery chain measured a TDS of 322. Those are undoubtedly safer to drink and use with fish. Note though that one was over six times the TDS of the other.  We may still need to add water gradually to a tank and to carefully adjust new acquisitions to their new homes. See http://www.guppylog.com/story/2005/9/7/145228/6771
on acclimating new fish to an aquarium.

Do you need a TDS meter if you are not a really serious (maybe crazy) aquarist or gardener? No!

But we (certainly I) need to read the small print with the contents more carefully. The two waters with positive reading, in addition to the RO water, contained Calcium Chloride, Sodium Bicarbonate (bet the pH was higher in that one) and Magnesium Sulfate in one mix. The water, which tested 322, didn't say what was in there!

And we need to adjust water to tanks and the fish to different waters gradually.

There are other issues pertaining to tap water and aquarium fishes, which have come up lately. They will be touched in another diary, "down the road." ;)

Associated with that, is there a traditional day when people, especially home makers, wash clothing? I'm pretty ignorant of that. I threw some stuff (same colors) in the wash this morning, but that is on the "We don't need fish water this AM, the laundry basket is full and my wife might be absolutely amazed if I got off my lazy butt and put something in the wash" basis.