need help on water chemistry... please!

[aussiefishy]

Hello Dr. Ron:

your answer can be more indepth because i have couple years of schooling in university chemistry.:rollface:

my friend's tap water is somehow weird....

whenever we use the tapwater to fill up a glass tank in the basement of his house, when the water is aerated for a night and brought up to temperature, the pH is 8.8, then when saltmixes is put in, the pH drop to 7.8 and white powery stuff are covered everywhere, and sometimes, the water is quite murky.

this afternoon when we are checking the QT's pH, it is abit low so i added some KENT marine pH buffer in there, it says it makeup of carbonate/bicarbonate salts.. and as soon as added in there, the pH rise a littlebit and fall, at last the tank starts to turn cloudy and white, powery , hard film of stuff attached to the glass of the tank... the pH fall below the value before the buffer was added...

BUT! he uses the same saltmix, water in his main tank, whenever the pH is low the same buffer is addded and it is fine!!!! the tank has some argonite and LR's and water wasn't cloudy.

i can make sense that the white stuff is probably a precipitation reaction from the buffer, so these white ppt are carbonates... but why??

BTW, he just bought a RO/DI unit, will this solve some/all of this problem??

Please help as i am very very confused at the moment.:confused:


Eric

[rshimek]

[moved]

[Randy Holmes-Farley]

First, I don't generally recommend tap water for a variety of reasons outlined in this article:

Tap Water in Reef Aquaria
http://www.advancedaquarist.com/issues/jan2004/chem.htm

Second, tap water can contain a lot of carbonate alkalinity and/or calcium (shown in the article), either of which could possibly lead to a situation where calcium carbonate would be inclined to precipitate from a salt mix.

Third, adding a buffer is not a suitable way to raise pH. The alkalinity gets too high, and can additionally result in more precipitation of calcium carbonate. These articles should help:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

Adding an RO/DI (and not adding additional buffer) should be a help. :)

[aussiefishy]

this is what i have got from the water quality report in calgary, Canada

Hardness as CaCO3
122 - 251mg/L limit = < 500 mg/L

pH
6.98 - 8.18

Calcium
33.2 - 67.7mg/L

Magnesium
9.8 - 18.5 mg/L

Free Chlorine residual
0.52 - 1.32 mg/L

Chromium
not detected - 0.005mg/L

Copper
not detected - 0.003

i am sure i can benefit somehow with a RO/DI units, but i just want to know if the water is useable. the reason is because i uses tapwater and it is fine for me... we both lived in the same area....

please help!



:eek1: :eek1: :confused:

[Randy Holmes-Farley]

As I mention in the article above, my biggest concern with tap water is copper from your own pipes (which won't be in the report). So even your next door neighbor may have acceptable water while you may not.

FWIW, there is quite a bit of calcium and alkalinity in that water. That can be good, as a free additive, but can also be bad as it slowly skews the water away from your desired balanced target.