I'm sure there are some fish that prefer high sulfate water. I was just
assuming most tropical fish do better in reasonably low sulfate water. No
real data, but in the back of my head, I think sulfates tend to be higher in
arid regions.. could be wrong.

High sulfate water is related to all sorts of increased diseases in
humans..(so is super soft water or super hard water). The geographic
correlation between groundwater and disease is an interesting subject. Too
little or too much dissolved solids in water isn't good... over a life time.
Unless you are in parts of NE Wyoming where MgSO4 is common in the water,
then it is rough in the short run.

Very:-) Makes you wonder how the first folks that lived there found
out the hard way.

I know a number of rift cichlids that do well in high SO4, K+, Ca,
Mg, CO3, levels even if you depress the pH with CO2.
Folks worry too much about pH IMO.

Fortunately, Gillette has had the
pipe line bringing in Madison Formation water for years. What this has to
do with fish I don't know ;-)

I've been through Gillette,(few folks stop there except to see Devil's
Tower) and most of WY. Mg SO4 content can have plenty to do with
fish/plants.

My thought was basically why add something to a tank that you really don't
need and isn't going to be utilized by the plants to any high degree. Also
sulfates are involved in certain types of biodegradation....sulfate reducing
bugs, methane is a common by product.. Not a bad thing when dealing with
gasoline of other hydrocarbon contamination... I don't know what they'd
produce in an aquarium.... I'm a geologist not a bio-chemist.

Bob

I forgot to mention the Cl2 from the CaCl2 might be worse actually
than the Dolomite.

Powdered dolomite would be perfect I think and it's cheap(not sure
about powdered form).

Better than the CaCl2 and MgSO4 mix if they want KH as well.

Regards,
Tom Barr