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An
Article by George J. Reclos
This is the second attempt to
start a marine tank.. in a small scale. The first attempt was unsuccessful
mainly because I hadn't invest enough time to study before but rather
tried to solve the problems as they were coming. Of course this is the
wrong way to start anything, especially a marine tank. I ended up with a
completely unstable system which - of course - crashed.
This time I did my homework and I started everything from
a scratch. One of the 140 liter tanks was cleaned, the filter media was
removed and cleaned, even the sand was mixed again and washed. After that,
I prepared the synthetic sea water and installed the basic equipment which
are supposed to support this "basic" tank. An air driven skimmer (supposed
to support a 200 liter tank), one heater, two air pumps (one for the
skimmer and one to aerate the water) and two internal filters (a total of
2000 l/hr). The final goal is to set up a 500 liter fish only marine tank
with two 100 liter sumps.
Then comes the question of cycling it. With fish or
without ? Up to now I have always cycled my tanks
with fish or using
elements from already cycled tanks. Here I decided to start the fishless
procedure. According to the book, you just add bacteria every day and you
feed them with an ammonia containing stuff every other day. Sometime
between 2 weeks and 2 months, your tank should be cycled !
It looks ready to house the first inhabitants but it is
not. The nitrite levels are still too high (not to mention the nitrate
levels which are out of scale). I can hear
some of you wondering if everything went by the book.. Well, obviously
not. To start with, I read the books, tried to understand how this these
things work, asked many questions (Robert Fenner and Andreas Iliopoulos
really suffered during this time) and then I adapted their input to my
need for experiment. So this tank is cycled without fish and I use plain
ammonia to speed up the procedure.. Well, this sounds very easy, why not
everybody does that ? To start with, you can find an ammonia solution in
the pharmacy but knowing what its concentration is.. well this IS another
story. Most people who sell ammonia solutions (apart from commercial
chemical companies) do not know which is the concentration of ammonia in
the bottle. Moreover, ammonia is volatile and will try to escape. To make
things even more complicated, water can "keep" less and less ammonia as
the temperature rises. For example, you can have a 50% ammonia solution at
almost freezing point while you can only have an 18% solution at 50oC.
Therefore, the first thing I had to do was to find out how much ammonia
was there in the bottle. This was done by a volumetric titration of the
solution (Ok, I am finished with the technical terms) which revealed that
the starting concentration was 18% w/v. Most probably the guy had stored
it for years. Note: if you try this, once you determine which is the
concentration of ammonia in your bottle, just keep it refrigerated. This
will keep your solution stable for a very long time. Apart from cycling
your tank you can also use it to check your kits !! Freshwater hobbyists
can also use this method, after all I am still a freshwater hobbyist and a
saltwater newbie. So let's see what a newbie does..
After making the calculations to see how many ppm
correspond to that 18% (actually this 18% means 18 grams of ammonia / 100
ml water, which is directly translated to 180.000 ppm ammonia) I added
enough microliters (1 microliter = 1 millionth of a liter) of this
solution in a liter of double distilled sterile water and used the kit I
have to see when I would get a reading of about 4 (with those colorimetric
kits it is quite difficult to
say and 4 was the high end of the scale). However the kit (Mydor) proved
to be only 20% off the calculated value (It read "4" when I knew I had
added 5 ppm) and was thereafter used as a basis for the calculations since
this would be used with my tank water. Using analytical methods is far
more expensive and time consuming besides making this article useless to
most of you. Once this was achieved, I adjusted my calculations for a
level of 6 ppm and added the necessary quantity in my tank (I first added
the ammonia in 100 ml of water and then dropped it in the tank). I
repeated this procedure every two days, while adding the "useful" bacteria
each day. On day 2 I had an off scale reading for ammonia (this was
expected) while nitrites (Aquarium Systems) and nitrates (Mydor) were not
detectable. However, on day 8, I had no detectable ammonia, nitrites were
up to 8 ppm and nitrates off scale ! Well, this was pretty quick even by
my own standards..
Then I had to solve the problem of feeding the established
NH3 consuming colony. It was evident that if left alone the colony would
starve to death since there were no producing elements in the tank.
Therefore, after the NH3 dropped to almost 0, I kept on adding the same quantity
every day. Of course, this would be far more accurate if one was to know
what is the anticipated amount of ammonia a fish will produce per day. I
think that 6 ppm in a 140 liter tank is a bit too much for one fish. This
means that the biological filter will be calibrated for higher ammonia
levels that the ones the fish will produce therefore part of the colony
will die - polluting my water. That is why a fish cycling should be
preferred but one has to work with what is available to him !! On the
positive side, the amount of nitrites produced per day was really high
which should promote the growth of the second colony of bacteria. On day
10, I get NH3 = 0 ppm, NO2 = 8-10 ppm and NO3 well over 50 ppm. I will
keep you informed about the progress of cycling. It was also about the
time I enrolled Mike Iannibeli to the list of people I should
bother more with my questions !!
A small inexpensive air driven skimmer will probably serve
its purpose - which is to learn some things before going for the real
thing. I believe that accumulating knowledge and experience is the most
important thing to success.
One of the first surprises was the amount of organic
matter still present in a thoroughly washed ex-freshwater tank. Perhaps
this was due to some decaying "freshwater" algae which could have remained
on some rocks.
A detail of the wooden airstone
which is usually used for marine tanks mainly because its smaller pore
size allows for much smaller bubble size. Many small sized air bubbles are
mandatory for efficient skimming. Most "guru"
authors claim that overskimming is not possible so I chose a unit suitable
for a considerably larger tank than mine. The next issue I had to resolve
is the huge amounts of nitrates in my water (impossible to add a fish
under those conditions) and of course, the aquascaping of the tank. I
always find it important to have all my tanks decorated. I don't care if
it is a fry raising tank or a hospital tank. It has to be aesthetically
pleasing so I had to aquascape it. See next page for
more..
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