[APD] RE: calcium ???

["Steve Pushak" <teban at powersonic_bc.ca>]

Antonio Vitor wrote:
> I even have some very close macros (snails with 3 mm max) of
> my snails.
> And they are transparent!
> http://aquatico.no.sapo.pt/macros/5.jpg
> I guess this is confirmation of calcium problems!

I can't tell the scale from the photograph. I think some types of small
snails have a very thin shell that can be translucent. In my tanks if Ca
is low & CO2 levels are high, the snail shells will become eroded &
white. Once eroded, they never return to the proper brown color however,
where new shell grows along the front edges, it will be a nice shiny
dark brown if there is enough calcium in an aquarium. It takes several
weeks to see a change in snail shells enough to confirm something like
this. It won't happen overnight.

> My water company receives their water from many sources,
> the water changes a little from time to time.
> The other problem is they don't have recent detailed tests,
> and most of the time, it' s crap...

So did they provide you with any information? While the amount of a
particular mineral in the water may vary by -50% to +300% or more, any
set of test results would give some indication of the true levels of Ca
in the water. Since the tests vary according to the source of water, you
can ask for an analysis of water from each of the sources and thereby
bracket the ranges of Ca. If each of the water sources has a range of Ca
from 50 to 500 ppm, then you should be able to provide enough Ca by
changing water more frequently. You have to read the analysis carefully
since it may be expressed as ppm of CaCO3 not elemental Ca.

> Even with bi-weekly water changes I didn't manage to improve
> anything, it did get better for 1 day, but...I have 300W
> Metal Halide HCI (even more light than HQI), so everything is
> in fast gear, 2 days after and the same problems arise...

I don't think you would be able to observe much difference in only a day
but perhaps you can watch the growth tips of your Hygrophila and if they
are normal for a few days & then return to being wrinkled & distorted by
the end of two weeks, then it is a calcium shortage that is being
temporarily alleviated.

> I put some calcareous rock on my filter (it's almost pure
> calcareous), don't know if this will help a little...it was a
> big stone!
> I will also drop the use of MgSO4.

Until you know how much Ca and Mg is in your tap water, its difficult to
know if you can get away without supplementing it. You can add both
safely in the amounts that your plants will need & not worry. If you
have double or ten times the minimum calcium you need, everything will
be fine; just don't change the water hardness too much all at once for
the sake of the fish.

Calcium should be supplied approximately 3:1 molar ratio to magnesium.
If you are dry dosing you can use 1 tsp of calcium carbonate for every
10 gallons of water exchanged. That is about 3-8 grams depending upon
how fluffy or granular the CaCO3 is. I won't work out the % of Ca in a
gram of CaCO3 or Mg in MgSo4*6H2O (Epsom salt) but its easy to do using
the molecular weights of each element. If you use 3:1 ratio by volume of
the dried powders, you're close enough for growing plants. So if you add
1 tsp of CaCO3 then you want 1/3 tsp of MgSO4. For Europeans who use
metric measurements that would be about 1.5 grams of CaCO3 for each 10
litres of water changed. Remember that if the Ca is being used up in the
tank, even though you have 150 mg/L of CaCO3, it will be diluted to
about a third or a quarter of that concentration.

Putting limestone or calcareous rock in your filter may provide some Ca
for a while however it may be too much initially and not enough after a
few weeks. Rocks quickly become coated with slime and will not dissolve.
If the rock is friable or porous, you may have too much hardness. Its
just preferable to dose CaCO3 as a fine powder which you mix with water
in a jar and then pour into the aquarium. If you're not changing water
every week or two, you can always add a little extra treat of CaCO3 now
and then, say a quarter tsp for a large tank every few weeks.

There are other forms that you can add calcium in. Calcium nitrate can
be used however its more difficult to find. It dissolves readily but
can't be mixed with other solutions since the calcium would precipitate
with any sulphated salt solution. Hydrated lime can be used but you want
to use much less and add it in small doses over time since it can
increase pH drastically. If the pH goes too high and you have a high
fish load, you can kill or harm your fish because ammonia/ammonium
becomes more toxic at high pH. I believe hydrated lime also typically
contains magnesium but you have to read the label to discover the
percentages & ratios.

Steve

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