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Re: Comments on water analysis





Gee.  I wrote a response to this that should have shown up in APD V3 #1071
but it didn't show up.  I'll try again.

> Hello all,

> I got a water analysis from the water company, and I would like your
> comments on it, especially in relation to keeping aquatic plants, what
> is already sufficiently available and what not? I guess iron is low.

Actually, with regular water changes your 0.02 mg/l of iron might be
sufficient.  Most things seem fairly well balanced, but if your plants
tend to drop old leaves before they should and especially if they have
small holes and dead spots in the middle of the leaves then you might add
a little potassium.  Magnesium is probably fine at 3.6 but if the plants'
color seems too light green then you might try adding a little magnesium.
Unfortunately the light green color isn't diagnostic and could be caused
by several things.

In looking at a water analysis like this, always remember that maintaining
fish in the aquarium always adds substantial amounts of nutrients to the
tank.  The nutrients in the analysis aren't all the nutrients that you're
supplying to the tank.

> Physical-chemical parameters

> average temperature          ░Celcius  11,5
> dissolved oxygen             mg/l O2   10,0
> turbidity factor             FTE       0,13
>                              pH        7,25
> satiation index              Sl        0,06
> rest ▀ activity              Bq/l       <1
> conductivity by 20░ Celcius  mS/m       36
> oxidizability with KMnO4     mg/l O2    0,6
> UV-extinction 254 nm         m-1        2,6

> Anorganic parameters

> hydrogencarbonate         mg/l HCO3   116
> CO2                       mg/l CO2    2,4
> aggressive carbonic acid  mg/l CO2   <0,5
> Chloride                  mg/l Cl     46
> Sulphate                  mg/l SO4    37
> Sodium                    mg/l Na     22
> Potassium                 mg/l K      1,2
> Calcium                   mg/l Ca     50
> Magnesium                 mg/l Mg     3,6
> Total hardness            mmol/l      1,4
>                           ░DH         7,8
> Ammonium                  mg/l NH4   <0,01
> Nitrogen                  mg/l NO2   <0,02
> Nitrate                   mg/l NO3    0,2
> Orthophosphate            mg/l PO4    0,03
> Silicic acid              mg/l Si     6,5
> Iron                      mg/l Fe     0,02
> Manganese                 mg/l Mn    <0,01

> Am I right in the assumption that the KH is 1?

I calculated 5.3 degrees KH.  My Tetra test kit would read 6 degrees.

> According to the water company the amount of chloride is neglectible,
> but seems high against the maximum of 150 mg/l that the law permits...? 

Chloride has little effect on plants, so your 46 mg/l is fine.

> Also on a side note I read here law doesn't permit a pH lower than 7.
> Why is that, is there something wrong with drinking acidic water?

There's no direct effect from drinking water with a pH somewhat below 7.
Water with pH < 7 is sometimes "aggressive".  It can cause unusually rapid
corrosion of metal pipes, so water utilities want pH > 7 to save on
maintenance costs.  Also, water with pH < 7 can carry more toxic metals -
lead and copper, for instance - than does water with pH > 7.  That
probably is why your regulations want the pH > 7.


Roger Miller