Starting a Marine Tank I

Starting a Marine Tank I

Written by George J. Reclos Friday, 29 March 2002 00:00

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Starting a Marine Tank I
Page 2: Adding Fish
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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 litre 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 litre 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 litre fish only marine tank with two 100 litre 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 doing the sums 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 microlitres (1 microlitre= 1 millionth of a liter) of this solution in a litre 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 over-skimming 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.

The main issue was to use something which would be nice and as effective as possible. If this was a freshwater plant I would simply add plants. Of course there are no plants to be used in a marine aquarium but there is something quite close to it. Macroalgae. After a short visit to my friend Minos Pagonis (you can see his tank here and you will immediately realize the difference between a newbie and an experienced hobbyist) I got some Caulerpa sp. (most probably Caulerpa taxifolia although I am not sure)  for my tank. I will confess I was really attracted by this "plant". I am now determined that (if the Caulerpa in my tank thrives) I will go for a marine "planted" tank !! On day 11, several cuts of Caulerpa were added in the tank.

Everyday measurements for the nitrogen compounds are a must since it is the only way to know where each part of the cycle has been completed. In the table below you can see all the values and additions done during the first 30 days of this tank setup. Day 1 is November 25th, since the tank was actually set up on November 24th. Density = 1.025, temperature = 27 C, water regularly added to compensate for the evaporation.

On day 15, a third internal sponge filter (470 l/h) was added to the system. Thus the total water turnover was increased to 2470 l/h. The addition of the new filter was done in order to increase the surface on which the bacteria can grow.  On days 12 and 13 a liquid plant fertilizer was added in small quantities (Thanks, Mike). On day 16 a third lamp (marine full spectrum) was added to encourage the growth of Caulerpa.

Five days after the addition of Caulerpa I can't tell if it is growing or stalled. I can see some lighter colour at the edges of the stems but no new "leaves" seem to come out. Parts of the branches have turned dark green which - although I am not a specialist - do not seem like a good sign to me.

Compared to freshwater tanks which I stock almost immediately (using aged water and already seeded filter material) the waiting stage is indeed prolonged. Patience not being one of my virtues I feel like tied on my chair. However my short previous experience has taught me that rushing it can only bring disaster. Up to now it seems the only real difference between freshwater and marine tanks is time. A marine environment needs considerably more time to be stabilized. Needless to say, more and more questions were asked to more and more people throughout this process. Yes, I have my books, I can see the graphs in there but I want to get as much information as possible.

The tank is still not completely stabilized therefore the lionfish will have to wait a little more. This is what I found the toughest part of cycling to be.

It looks small (right tank) but it is a giant step for me. Lots of new bottles, jars, buckets and tubes have already appeared next to it. For the Malawi cichlid aficionados the left tank is the house of the Copadichromis borleyi sp and Pseudotropheus msobo (all F1) which were donated to me by Francesco. The male Copadichromis borleyi and the female Ps.msobo are clearly visible.

Last time I counted 45 elements in the various bottles and vials in front of this tank; this is almost half the periodic table!! If you can think of something else, please let me know. I have also added a much larger skimmer unit (in addition to the air driven one which was servicing the tank). I know that actually there is not enough space for a fish now but this time failure will not be due to overlooking the basics.

Although there are no fish in the tank I have high nitrites and nitrates (!!) and a lot of things which are apparently not needed. Photo of the small skimmer's cup - Dec.2001

I hope there will be a next page to see!! Finally, there will be a next page!!

The effort is still going on. After the 30 days were completed something seems to have changed, namely the level of the nitrites in the tank. As far as the nitrates are concerned you should have in mind that all this ammonia I had been adding for so long has been transformed to nitrates and only a good deal of algae plus a water change will lower its levels. On day 32 the nitrites have gone even lower so I decided to reduce the amount of NH3 added daily. This would show me on the spot if both bacteria populations were functioning properly. Indeed nitrites plunged to 2 and finally by day 35 they were at normal levels (0.8). It was about time, isn't it ? Well, now I had a cycled marine tank (yes, this calls for a celebration) but I had no fish in there and, if this was prolonged I wouldn't have any bacteria in there, too !! So I should add something.

 

 

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