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Your first aquarium – Part 2

In the first part, I explained considerations concerning a first fish tank. Now, let’s see how to set up your aquarium and launch it. This article does not want to address every issues in deep details, but wants to help you getting started while avoiding the common mistakes novices do.

Leak test

Before setting up an aquarium, you must absolutely test it for leaks. It doesn’t matter if it was bought new or used, all tanks may be defective or get damaged during travel. No amount of leaking is acceptable, not even a drop a day. Once your aquarium is started, it may be difficult to notice leaks, and if a leak is discovered it may be extremely difficult to take care of. Do not skip this step.

Cat in an empty fish tank

Tear the box apart. Ask a cat to inspect for visible defects. Remove foams and cat. Fill with water.

If the aquarium comes in a box, put it on the floor, ideally not far from the bath – you will have to empty it later. Tear the cardboard around the aquarium rather than take the aquarium off the box. You will never use that box again and it’s not a good idea to pull the tank by holding the top or the sides, therefore it’s a lot easier and safer to just tear the box apart. Just leave the tank on the cardboard. If there is polystyrene foam under the aquarium, take it off. If the aquarium doesn’t come with a box, I like to put white sheets of paper underneath, such as a thick layer of scott towels. In any case, you want a way to detect small leaks, which will not be visible if you leave the tank directly on the floor.

Put just a small amount of water at the beginning, just enough to cover the bottom, and check for any obvious leak. Pay attention not to accidentally spill water near the tank, which might be confused for a leak, or prevent you from detecting leaks. If you are satisfied, add more water, and keep looking for any obvious leak. Usually, I fill about a third of the tank and leave it alone for an hour or more, and check the cardboard or paper for any sign of a leak. If everything is fine, I fill it another third and wait again. Eventually the tank is filled completely. Leave it there for at least 24 hours, ideally 48 to 72 hours, and check regularly for any leak. Do not fill the tank and immediately go to bed, a leak might become apparent during the night and provide for quite a bad morning. Make sure you have a few hours ahead before starting the leak test.


Before you put the aquarium on the stand, it must be perfectly leveled. Use a level tool, either electronic or the good old bubble level. Do not trust your eye. I have yet to see a leveled floor, so you will need to make adjustments. Do like the pros, and get these sticks that you get for free in hardware stores to mix paint. I like to break them in three pieces, with my bare hands. Pile as many as necessary to level your stand, pushing them underneath the stand feet. When you are done, check that you would be comfortable dancing on top of the stand. Do not actually dance on it.

Do not put the aquarium directly on the stand. Even though you chose a good quality support, it may still bend a little or move over time. Remember, your aquarium will likely stay in place for several years, it’s better to plan ahead. To absorb any such deformation of the stand, it is suggested to put a layer of polystyrene foam under the tank. This will help diminish the impact of a surface that is not perfectly flat, even if it is not visible to the eye.

Foam flooring tiles covering my stand

For smaller aquarium, you could cut a piece out of an exercise mat, the kind that you roll when you store it away. I found these were surprisingly expensive though, and I found a better and less expensive solutions. They sell polystyrene foam flooring tiles that you can use in areas of the house where you frequently stand, such as the kitchen, for comfort and safety. These are available in most department stores. They are sold by individual tiles, or in packs of four or such. You can assemble two tiles or more to cover your surface, and cut any excess with a knife. Leave a few centimeters / an inch around the aquarium, as the ends of the mat will curl up when you fill the tank with water (it gets heavier); do not cut the mat to exactly the size of the tank.

There are quite a few pieces of equipment that will need to be plugged in. I always install a power strip on one side of the stand, at the very top of it. It serves several purposes. It will let you have more outlets. You can turn off all of your equipment at once, if something goes wrong or for cleaning. By putting it high, it forces a drip loop on every cable.

Tank, finally

Prevents water drips (from spills, leaks or condensation) from reaching the power outlet

Prevents water drips (from spills, leaks or condensation) from reaching the power outlet

Now is the time to put the tank on top of the stand (make sure you emptied it before moving it). Before settling it into its permanent position, take a minute to clean the back glass; you will never get another opportunity. Check that the tank is perfectly leveled – if it is not, readjust the stand, not the tank itself.

Most people prefer to fill the substrate first, and then the water. Others like to put a small amount of water first. Do not wait until the tank is completely filled with water though. You will need between 1.5 and 2 pounds of substrate for every gallon of water. This is a rough estimate, of course, make adjustments based on whether the tank is wide or high. 3-5 cm / 1.25-2 inches is fine. If you want plants, go for a thicker layer of substrate. It may appear like a lot at first, but you will soon realize that there is never enough.

Colored gravel sold in stores is perfect for a first setup. Most people prefer a darker color substrate so the fish colors appear brighter. Furthermore, fish seem to prefer darker substrate. If you intend to keep plants, you may want to use a smaller size gravel to hold the roots better.

Sand has became popular as substrate, in particular in saltwater. It is believed to be more efficient for bacteria. However, there are many risks associated with sand, and sand is therefore not recommended for beginners. Sand cannot be cleaned as easily as gravel. If not cared properly, it could accumulate debris which could turn into toxic gas which could kill fish. Also, sand can obstruct your filtration system. It’s better to get informed before you settle for sand as substrate.

Fill in your tank with tap water. Most people like to fill it just enough that the surface line is hidden behind the top ring or border. You may want to put a little less initially so as to not spill water as you proceed with installing your equipment and decorations.

Install your filtration system – read the instructions that came with it – and turn it on. You should also install your heater, if you intended to use one. You may also put any decoration.

You may also install your lighting, but you may want to leave it off during the initial cycle. Light is not beneficial at this stage.

Now, wait a month.

Nitrogen Cycle

An aquarium is an ecosystem. A large amount of bacteria will work in there, their task being to decompose things, such as fish poops and extra food. From these trash, bacteria produce good and bad chemicals. Bacteria are desirable and part of a normal and healthy aquarium.

You must give bacteria time to develop. This wait time is called the nitrogen cycle, or often just the cycle. A cycle normally occurs only once and lasts about 3-4 weeks in a new freshwater aquarium, and up to 6 weeks in a saltwater aquarium. In the middle of the cycle, the level of toxic chemicals in your aquarium will be very high, which would kill most of your fish. You must not put anything alive in your tank until the end of the cycle. Loosing fish during a cycle is a novice mistake that we often refer to as the new tank syndrome.

Freshly filled tank, 110 L / 29 gal. I mixed black and blue gravel for a total of 60 pounds.

Freshly filled tank, 110 L / 29 gal. I mixed black and blue gravel for a total of 60 pounds.

The nitrogen cycle is quite simple to understand without going into advance chemistry. Everything that gets decomposed is turned into ammonia, and then into nitrite, and finally into nitrate. Each step is performed by a different set of bacteria. If you were to regularly test water with test kits, you would see a peak in the level of each of these toxins, in order, a few days apart, with the ammonia after about 10-14 days in freshwater or 14-21 days in saltwater.

You must perform water changes and clean your filter regularly during the cycle, even with no fish.

Waiting a month is usually safe enough, but for extra confidence you can buy a nitrate (NO3) test kit. Your bacteria colony is ready when the test shows no trace or very low level of nitrate. At this point you can begin introducing your inhabitants, but do it slowly.

It is common to get a small algae bloom during your cycle, or soon after, but don’t worry as it should not last longer than a week or two.

Products are sold on the market to get rid of the cycle. Often designated by hobbyists as bacteria-in-a-bottle, their efficiency vary by brands and users. Some people claim to use them and be able to put fish in the tank immediately, claiming to never have a nitrogen cycle. Others use them as helpers during their normal cycle. Many more wouldn’t approach these products with a pole. I tried two different brands in two different occasions, as a helper, and didn’t get any appreciable result. Your experience may vary.

If you intended to get plants and snails, introduce them first. Wait about a week before going with your first few fish. Each time you introduce something new, you will break the balance of your ecosystem. Your bacteria will quickly adjust to the change though, but this period is often called a mini-cycle as there may be a small increase in toxins. You can always use a nitrate test kit to check for any such development. Do not add too many fish at once.

Regular maintenance

Most people perform a partial water change once a week, or every other week. Every aquarium being different, you will have to learn how much maintenance your aquarium needs. Test kits are handy, especially in the early months, to see how the parameters evolve over time, and see what seems to be a good frequency for your particular tank. If all of your snails are at the top of the glass, desperately fleeing the water, than you need to perform a water change. If you have frequent algae blooms, increasing water changes frequency may help.

Do not ever completely empty the tank. Your mother did that for your goldfish bowl, but an aquarium doesn’t work like that. A normal, regular water change should not be of more than 10% of the total water volume. If you have nitrate problems, or if for any other reason you were told to perform a larger water change, you may go up to 20%, but that should only be on these rare occasions. Removing too much water is not good for your ecosystem.

Do not put fresh water right from your tap right into your tank (except for the initial filling). Tap water contains chlorine, which is added by your water utility to prevent algae and bacteria from developing in the pipes, and it will damage your ecosystem. Chlorine evaporates in about 24 hours, therefore you must leave water to rest for at least that long. The common recommendation is 48-72 hours. If you are in a hurry, chemicals are sold that will get rid of the chlorine in a shorter time. I let a 18.9 L / 5 gallon bottle to rest at all time which I fill again after any water change. As an alternative, you may use bottled water, which does not usually contain chlorine. You should be aware though that the amount of nutrients in bottled water is often lower than tap water, and as such it should only be considered if your tap water is not of very good quality. If you don’t know how to test your water, or do not own test kits, bring a sample to your fish store which will perform the analyses for a low fee ($20 or less) and give you recommendations.

For saltwater tanks, most people prefer to use distilled or osmosed water, either bought from a store, delivered, or prepared using home water purifying equipment. A suitable RO/DI (a reverse osmosis device) can be bought for $200 new, or $100 used (assuming new filters). In any case, salt must be added to the water and let to dissolve for about 24 hours before the water is added to the tank. In my case, I have saltwater ready at all time, which I prepare from bought osmosed water.

While you perform your water change, take the occasion to do some cleaning. You can clean your filter media in the water you just removed. You can clean the inside of the front glass – I never clean the other sides, I leave whatever grows there, it looks more natural, plus it feeds your snails. You can clean your substrate occasionally, but not too often, as it disturbs your bacteria colony.

Filter media contains an important part of the total bacteria colony. Cleaning them in the water you just removed works well because it minimizes the loss of bacteria. Do not clean them under running tap water because you would kill the bacteria with the chlorine in the water.

Filter media manufacturers most usually recommends changing them every month. Unless your aquarium is particularly dirty, you can get away with changing them less frequently. In most cases, changing them every three months is just fine. If there is a lot of visible detritus that cannot be cleaned off, or if the water becomes visibly less clear, it would be a good time to change them. Since the filter media hold part of the bacteria, you should not change all of the media at once. Instead, you should change a different one every month, until they were all changed, and then repeat the cycle.


Obviously, this is just a basic introduction. Do not think you know everything by now, but you should be comfortable with the basics. From this point on, you may want to buy a book, read more on websites, and even subscribe to a forum.

Feel free to ask any question, add in your experience, or express opinions in the comments below. I do not plan on bugging you any longer with posts about fish tanks, but if I get suggestions or a general interest, I may just as well write more in the future.

I recently found this blog, Cassie ~ Jux.ta.pozed which, among other things talks about fish a lot. From her own words, she is a specialist, not a generalist. She has articles about specific species of fish, but also a few about the nitrogen cycle and water parameters.


12 comments on “Your first aquarium – Part 2

  1. heretherebespiders
    November 6, 2013

    Two questions! I noted that you didn’t discuss under-gravel filters. Why not?

    What if your main fresh water source was a natural spring, how long would you leave that water to sit, or would you at all? Other than to get down to room temperature, of course – spring water is COLD.

    • Tom Duhamel
      November 6, 2013

      Good evening Madam,

      Two actually good questions.

      I’ve never used under-gravel filters (more often referred to as bottom filters in forums, or abbreviated as UG filter). They aren’t very common, they are mostly used in large systems, and as far as I am aware more in reef aquariums than anything else. They are not required, and (while once quite popular) are actually dropping in popularity.

      In a perfect world, UG filters are supposed to help the biological filter (that is, the bacteria) by removing excess debris from under the gravel (that’s were excess debris goes) and by improving water circulation. Many people are successful with such a system. However, UG filters require a lot more maintenance to keep them in working order, and this maintenance is usually a lot more difficult to perform.

      UG filters are risky. Gravel may pass through and block the pump of the filter (or debris may do the same), which could cause it to stop. Gravel may pack too tight over time and prevent adequate circulation. Stagnant water beneath the gravel is extremely bad (you end up with debris that the bacteria cannot take care of easily), leading to a major increase in ammonia and nitrate. Also, a blocked pump could well produce excess heat. Since UG filters are for the most part concealed, any such problem might not be detected until it is too late.

      If your tank is not overstocked, and maintenance is adequate, and if your bacteria colony is well established, this type of filter should not be needed at all.

      In the end, a lot of aquarists simply believe the risks involved with using a UG filter is simply higher than the potential benefits.

      Spring water does not contain any chlorine, so obviously you don’t need to leave your water to rest for this reason. But as you figured, temperature may be another reason to let your water to rest, and I sure forgot about this one. The reason is that my saltwater tank (the one I have been running for over a year now) was a temperate water tank. I kept it at 18ºC, and it was actually painful to keep it this “cold”. The colder was the new water, the better it was. Also, I tend to have water ready (salt and now fresh too) at all time, so my water is always at room temperature anyway.

      Obviously, it’s better to add water that is close to the tank temperature. In tropical aquariums, people commonly use a heater right in their resting water, so it’s always at the right temperature. My saltwater tank only contains sticklebacks now, who’s ideal temperature is 21, so I just let it at room temperature (it tends to remain at 20 now). I will probably keep my freshwater tank at 22-24 (not totally decided what I’m going to do with it yet) so I will probably not get concerned much about temperature of the new water.

      Those who keep reef tanks, or tanks with deep water fish, are very concerned with temperature, because in the deep see temperature stays extremely stable, within half a ºC. For the rest of us though, most fish don’t mind a small variable of 1 or 2ºC, and a small 10% is unlikely to cause such a variation if your water was at room temperature in the first place.

      To answer your question, it would depend of how much water you keep to sit. A small amount (5 gal) will likely be warm enough after 24 hours, for a larger amount you will need to see for yourself. May depends on where the container is left in your house (I wasn’t heating my bathroom in my old apartment, so the water was always at 17-18 — but now here it’s in the living room so it gets up to 20). I do recommend everyone would have water ready at all time (your container will use up space, full or empty, so doesn’t matter). But a heater is not very expensive, so you may use one if you want your water ready faster (but still, it won’t make your spring water ready in an hour, obviously).

      Are you getting your tap water from a spring/well? Or was that just for curiosity?

      Hope these answers were adequate. I can sure improve them if you need more specific details (details which you won’t even use lol).

      • heretherebespiders
        November 6, 2013

        I like to learn, just in case! And also to find out what I did wrong when I did have fish (fresh water only).

        We do ‘go to the well’ about once a week for our water, for ice, coffee, cooking, etc. We run it through a filter first, of course, and have to sterilise the 30L container every few weeks as it starts turning greenish at the bottom! We don’t give it to the animals, and hubby makes his tea with tap water but I hate the way it smells.

        I did have an UG filter, and thought it was much easier than the packet-type ones. It had a rotating top filter also, and it seemed to aerate the water quite well while also keeping the bacteria fresh and happy. But that was in the 90’s 🙂

        • Tom Duhamel
          November 6, 2013

          Ah! Things have changed a lot in this field since the 90s. In fact, it changed so much in just the last decade that I constantly need to check the date on everything I read, and check with other articles, to make sure the information is still accurate. In fact, forums are filled with “not anymore” replies and explanations.

          Of course, you know what the green stuff is. That’s what chlorine in tap water is for. Just a stupid trick, but make sure you don’t leave the water to rest in light, and most particularly sunlight. Your water shouldn’t contain any nutrients the algae need, but it will grow nevertheless if they have enough light.

          I learned this trick early on, and I keep my water in a black container, actually a large outside trash can (which I bought new of course, never been used for trash). That’s for saltwater, I will buy another one for fresh water too (I found I will need to dilute my tap water, so I will need something to mix it anyway). For now I have two 5-gallon translucent bottles, but I keep them away from direct light.

          I should have mentioned that in the article too, I forgot. But whatever water you are going to use, it’s better to have it tested (mainly for pH and hardness), it varies greatly from one place to another. My tap water is “too rich” for what I intend to do, so I’ll probably cut it with osmosed water (which I already buy to prepare saltwater).

          So far, any clue as to what went wrong? Maybe you could describe what you remember, maybe I (or someone else) will get a clue. How did you performed your water changes, as compared to what I wrote? What fish was in there? How long before it went wrong?

          • heretherebespiders
            November 6, 2013

            I wouldn’t say anything went wrong! I just, um, moved out and left the fish with my former partner. We never got crazy into it, but my favourite was a fish we named Bonk. It was an ugly dragon gobi, who would swim the long way down the tank, slowly, until it hit the short side – BONK! I always likes oscars, as the first one I met would ‘dance’ inside the tank when the food packet was shaken outside. Seemed pretty damn smart for a fish, but I never wanted to subject one to my lackadaisical care taking.

            • Tom Duhamel
              November 7, 2013

              I see you are more in big fish. Oscars are great fish, but not exactly the kind I would want to own.

              Fish react to stimuli, which for us resemble intelligence (yeah, sorry for breaking that for you lol). Every fish tend to react to the presence of a human near the tank, as they associate our presence to the sudden appearance of food. I doubt they really understand where the food is from, or for that matter, that they even question this. But maybe they do, I don’t know.

              My crabs were really cool. Within a week of being there, they knew feeding time was approaching, and they began running around crazily in the tank, waiting for their food. They were fed only every other day, and if I approached the tank on days they weren’t being fed they didn’t do anything at all.

      • Cassie
        November 8, 2013

        I have tried an UG Filter. It was on sale and fit a twenty gallon. It is ugly outdated technology and the water under it does get stagnant and it is a pain to tear apart and clean. Everything you mention is very true in regards to them.

        I would not like to mess with my water that much, I feel lucky being able to use it out of the tap and just dechlor it. Lifting buckets Ugg what a pain.

  2. 메간 Megan
    November 7, 2013

    My favorite part is the leak test 🙂 So cute.

    • Tom Duhamel
      November 8, 2013

      I hope you mean you found the cat cute. Because I don’t see what’s cute regarding a leak test as is 🙂

  3. Cassie
    November 8, 2013

    Great job Tom! Good article and thanks for the shout out. 🙂

    Absolutely leak test at a minimum of 48 hours. Another trick to leveling is to level when the tank is half full and recheck the level after is is filled. Do not eye ball it. Drain and fill as many times as you need to. I use card board folded up to level, it is more readily available to me and i can trim it to hide with a box knife. I also cushion with the foamy shelf lining stuff ( I dont know what it is called) it comes in black and is $2 a roll.

    You didn’t mention how to kick start a cycle. For a fishless cycle it is easiest to just use a tiny pinch of food every few days. Freshwater is different than salt in the way a cycle starts. I cycle fish in if I don’t have an extra cycled filter lying around. But did cycle fishless once. I do disagree that a cycle is stable after the bacteria colony establishes itself and new tank syndrome is a set of problems that can occur even after you have BB.

    In regards to water changes. It also depends on species, tank size and maintenance schedule. 10% is a minimum recommendation. For my angel tank that is only 5 gallons every-other week. I actually do 50% to 75% to replenish the needed minerals.

    I think you will find my fish article scheduled for this weekend amusing.
    Cant wait to see your tank up and running

    • Tom Duhamel
      November 8, 2013

      Thanks for the compliment 🙂

      Regarding the roll of foam, nothing this cheap seems to be available in my area. I did consider many things when I looked for that back in the time, but the flooring tiles I ended up using is what is the cheapest I could find, and it’s kind of thick so that’s good for me. In home hardware stores, they sell rolls of foam, but it’s extremely expensive and the minimum I could buy was so high it worsened it.

      There are lots of tricks to help start the cycle, and I considered having a paragraph to share some of these methods. However, each of these tricks come with a risk that I would have had to mention. It eventually sounded overwhelming considering the target audience, which was really people that had no clue. If you already have another tank, it’s easy to bring bacteria from one to another (reusing old filter media, some of the decoration or even plants), or put in some fish that you can take back when ammonia kicks in (you better know what you are doing for this last one, isn’t it?). There is also the possibility to borrow some decorations from a friend, but you better trust that friend since you could accidentally bring illnesses or other bad things. In my case, none of these could be done anyway. I know some people use liquid ammonia, but this is very risky, I wouldn’t even think of doing this myself (with three cats, I wouldn’t want to have toxic stuff in my place). Overall, a long waiting time with a completely empty tank seems the safest method for someone who is just starting (and this is actually what I’m doing with this one tank). Going very slowly, you end up with a good colony eventually. Your house is already full of bacteria that will settle in your aquarium, and that is why you wouldn’t leave dirty dishes in your sink for an entire week. Also, an empty tank is not really empty. The first few bacteria to settle in will die because they have nothing to eat, and will become food for the next set of bacteria.

      I’m surprised you do such major water changes regularly. Your reasoning sounds good to me, and I assume your system adjusts to that. But consider the very large amount of water as compared to what you have to use the nutrients (fish and plants). Nutrients aren’t depleted this quickly. 10% is the most common method (that’s what I do too), but you are surely not the only one to believe in larger water changes. But then, there are people that never ever do any water change, so every method may work, when you understand what is going on.

      You may have noticed I didn’t mention the effect of plants on ammonia/nitrate and the cycle in general. I know you are into plants, so surely you know of it. I considered this wasn’t necessary knowledge for a novice. If Spiders decides to start a tank, I’ll tell her, because she is the kind of person I expect to have more plants than fish lol

      I will post pictures later, when the new tank is running. Have you checked my YouTube videos? I posted videos showing my saltwater tank back in the time it looked good (I would be ashamed to show what it’s looking right now — in fact I decided to empty it and start it anew, I’m undecided as to whether to make it a tropical one or more of the same style).

Any question? Have a tip to share? Have a different opinion?

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This entry was posted on November 6, 2013 by in Aquariums and tagged , , , , , , .
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