Basics : Water
The easiest approach for a new hobbyist, is to purchase fish which match the the water available where the aquarium wil be located, rather than trying to alter the water conditions to match a fish's requirements. Speaking of requirements, unless you are trying to breed fish, their basic requirements are to have clean and stable water conditions which are not to an extreme from what they are accustomed to. If this can be achieved, then there is very little chemistry to be used, but some basic knowledge is needed to achieve this harmonius state.
Start by determining if your local water conditions are generally hard (ie: well water), soft (ie: river water), or neutral (somewhere in between). With only this rough knowledge, you can be guided to a better category of starter fish. For example, with hard water, livebearers, goldfish, rift lake africans and many rainbowfish are a good fit. With soft water, danios, tetras, gouramis and most other cichlids will do well. Almost every fish will be ammeniable to neutral water conditions.
Soft water (low in minerals) is generally acidic (pH < 7) or neutral (ph =7), unless it has been artificially changed (which is what municipal water treatment plants do). Hard water (high in minerals) is typically base (alkaline, pH > 7). Generally, municipalities must make public to anyone asking, what the exact water parameters are, and pet shops often do these tests for free as well, but don't let them tell you that your water is 'fine'. Note the exact parameters down for future reference.
A new tank setup requires a break-in period of 4 to 6 weeks. This is called cycling the tank, or more appropriately, New Tank Syndrome (NTS). During this time, don't have many fish, feed sparingly and do lots of water changes. The parameters of concern will be ammonia and nitrites. I discuss methods to avoid NTS and there is a section on bacteria trivia.
If the aquarium is neglected, then the symptoms of Old Tank Syndrome (OTS) will begin to appear (ie: high ammonium and low pH, or very high nitrates), but this is easy to recognize and prevent if you are aware of it.
Once the tank is cycled, and if you keep a reasonable fish-load, do regular water changes and follow proper filter maintenance and gravel vacuuming, then the aquarium should run very well without complications. Any further chemistry should be optional, according to your interests and application.
By the grace of many chemists who have patiently answered all my questions over the years, I hope my details section is easily understood by other non-chemists, such as myself.
From the viewpoint of the nitrogen food chain, (what happens to that fish food), the topics of interest would be ammonia, nitrites and nitrates, and ammonium, especially if you are starting a brand new tank. If your water supply originates from a well then look into the following sections of well water, hardness, acidity & alkaline and buffer, and well water if often CO2 charged. If your water supply comes from a river (and most waterfront cities use treated river water), then the section on city water, will be of interest. Having determined what your water parameters are, you might want to know how to to harden them. On the other hand, if your water is too hard, then to soften them, there are several choices, such as RO & DI water, rain water & snow, and CO2 injection. Last but not least, the well debated topic of salt is also covered.
Details...
The operation's VP of a pet shop chain said to me that the basic thing that everyone needs to know to keep fish successfully is that you have to keep them fed and in warm clean water. Although simplistic, this is essentially correct (along with space & territorial considerations). Feeding them is easy, as is adjusting the heater. Keeping their water clean is the single most important aspect of the hobby.
(NTS) NEW TANK SYNDROME
Briefly: when the waste handling capability of an aquarium is lower than the rate at which waste is being produced (fish poop), the byproduct (ammonia) quickly builds up to toxic levels, to kill or cripple the tank's inhabitants. The ammonia spike, will typically be followed by a nitrite spike, which though less toxic, can be devastating to already weakened fish. The process of cycling a tank (building nitrifying bacteria to balance waste consumption to waste production) takes between a couple of days, to 6 weeks (depending on situation).
AVOIDING NEW TANK SYNDROME
One method is to add liquid ammonia to an empty aquarium and wait till the nitrogen chain has established itself, with the growth of the various bacteria. You will still have the ammonia and nitrite spikes, but with no fish suffering their effects, you have no concerns, other than doing a massive water change to dilute the final resulting nitrate accumulation. Your ammonia source should be as pure as possible (no additives to cause foaming etc). I've used AMEX Clear Ammonia from Wal-Mart with good results. Add small portions until your test kit indicates around 5 to 7 ppm of ammonia. Have your filters running (they house your bacteria), and leave your lights off (a dark environment is better for any bacteria in the water column as they are damaged by UVs). Without adding any 'seed' bacteria, your new tank will be cycled in 3 to 6 weeks. The required aerobic nitrifying bacteria exist normally in the air we breath, and will settle in the aquarium to begin multiplying. Besides liquid ammonia or fish, some other ammonia sources are rotting animal or plant matter (deli-shrimp, fish food etc).
Another method is to 'seed' bacteria. This can be done by either adding materials which came from a well established tank, or by purchasing liquid or powdered bacteria starter from a pet shop or on-line. If seeding from another aquarium, it should of course be a healthy aquarium, to not transport any diseases. Anything wet and slimy will have the desired bacteria coated on their surfaces, but for the vast numbers needed, the highest densities will be in filter media, such as a well-used filter sponge. When transporting the sponge, keep it moist and reasonable warm while between aquariums. Cycling can be reduced to days with this method. When you already own an aquarium, establishing a 2nd tank is as simple as moving an established filter (or it's filter media) over to the new tank.
When using purchased bacteria-starter, your results will vary from non-existant to highly effective. There are 100s of bacteria species, many of which would consider your water to be too hot, too cold, too acidic, too alkaline, too soft or too hard for their tastes, leaving only a minority to begin multiplying. Manufacturers are always improving their recipes, but it's a work in progress. Results can vary from very good to very poor with products which are sold refrigerated, as these can suffer from improper handling (thawed in transit). Freeze-dried and liquid products generally assist in minimizing the absolute total amount of ammonia and nitrites which appear, but the symptoms of NTS are still easily measured using test kits. Whatever seeding method is used, keep in mind that the bacteria must be fed, or they will die off. See ammonia sources above.
BACTERIA TRIVIA
Ammonia (NH3/4) is converted to nitrite (NO2) by nitrosomonas bacteria. It has been long held that the NO2 eaters, creating nitrates (NO3) were nitrobacter, but some recent research at Marineland points to a species of Nitrospira being responsible, additionally or solely. Using research done at NitroLabs, I've summarized some bacteria characteristics which could be of interest to hobbyists. I've no idea if NitroSpira's characteristics are similar to the NitroBacters, listed below, but then, we are just having a bit of fun with this.
To recap; NH3/4 => Nitrosomonas => NO2 => Nirobacter/spira => NO3.
The last part of the chain (NO3 => anaerobic bacteria => nitrogen gas) is not covered here. The anaerobic bacteria responsible for converting NO3 back into nitrogen gas (to re-enter our food chain) do not have a significant presence in the small ecosystems that our aquariums represent. A bit more on this is in the Filters page discussing biological filtration and filter servicing of sintered glass.
Note that the following characteristic will vary, depending on your setup's characteristics.
- optimum growth: 77-86F
- growth decreases by 50% @ 64F
- growth decreased by 75% @ 46-50F
- no activity at 39F
- death at 32F or 120F
- nitrobacter (makes nitrates) less tolerant of low temperatures
- nitrobacter growth, doubles every 13 hours (very slow!)
- nitrosomonas (makes nitrites out of ammonia) growth, doubles every 7 hours
(slow!)
- nitrobacter optimum pH 7.3-7.5 (african's, look out), inhibited at 6.0pH
- nitrosomonas optimum pH 7.8-8.0, inhibited at 6.5pH
- maximum nitrification rates exist when dissolved oxygen levels exceed 80%
saturation, inhibited at 2.0 mg/l (ppm) or less
- nitrobacter more strongly affected by loss dissolved oxygen than
nitrosomonas
- they require micronutrients (not found in RO, distilled or deionised water),
most common is phosphorus
- nitrobacter cannot oxidize nitrite to nitrate in the absence of phosphates
- nitrifying bacteria are photosensitive (bad), esp. to blue & UV light while
suspended in the water column
- chlorine & chloramines kill nitrifying bacteria
It's not recommended to alter you pH and temperature to accomodate the bacteria, as later you will change back to where you were before, and the bacteria you want are those which like your normal tank parameters. Having said that, optimal bacteria parameters would seem to be, no chlorine or chloramines, 81F, a pH pf 7.4 to 7.9, lots of aeration and having some trace phosphates.
(OTS) OLD TANK SYNDROME
Typically (and briefly), a large amount of detritus has accumulated in the substrate, and is rotting (acidifying and reverting to ammonia). In hard water tanks, this manifests itself as very high nitrate levels, which are difficult to control. In soft water tanks, this manifests itself as a pH crash, after the water's buffer (kH) has been consumed. Research topics are ammonium, acidity & alkaline and buffer. In both cases, aggressive gravel vacuuming is the most common cure, though in a pH crash condition (soft water), some caution must be exercised so that the pH does not bounce back up too quickly, stressing the fish, and converting non-toxic ammonium levels into deadly ammonia.
AMMONIA (NH3 or NH4)
After being fed, fish waste is either liquid (ammonia) or solid (which breaks down to ammonia as well). Decaying plant matter and uneaten food are also sources of ammonia. Ammonia cannot be allowed to accumulate as it is toxic. There are 3 ways to remove it: either continuously dilute to non-toxic levels (ie: water changes on an unfiltered fishbowl), or it is removed by living plants (which convert it into cellular growth), or it is consumed by bacteria. In an aquarium, daily water changes are not practical, and most people will not have enough plants growing to completely remove all the ammonia, so the bulk of the task fall to bacteria.
NITRITES (NO2) and NITRATES (NO3)
Nitrifying bacteria are aerobic (need oxygen) and they either convert the ammonia to nitrites (NO2, which is then only half as toxic to fish), or they convert the nitrites to nitrates (NO3, which is relatively non-toxic). Living plants will remove ammonia, NO2 and NO3 from water (in that sequence of preference). In nature, the NO3 also gets converted to nitrogen gas which makes its way back into the food chain to make a complete circle, returning as fish food. In the close confines of an aquarium, NO3 accumulates and is only removed by diluted through water changes, or consumed by plants.
Knowing that these nitrifying bacteria consume the fish waste, makes them 'good' bacteria and essential in almost any aquarium setup. Nitrifying bacteria will attach themselves to surfaces, ideally where there is a steady water movement to bring them a fresh supply of oxygenated water and their nutrients (ammonia & nitrite). This accounts for the slimy bio-film which covers everything underwater, and the brown colouration of your filter's sponge after a few weeks. This is the reasoning why your filter's sponges should never be excessively cleaned, as any significant damage to your colony of nitrifying bacteria can result in the re-occurrence of ammonia and nitrite (until the bacteria's population has balanced itself back up to the rate at which the fish produce ammonia). A good work-around after cleaning the filters is to reduce feeding for a day or two. Fish food starts the entire food chain (NH3/4 to NO2 to NO3).
HARDNESS (GH)
General Hardness is a measure of primarily calcium and magnesium. The gH affects the osmotic pressure across a fish's gills, and sudden changes will be stressful. Moving a fish from very soft to very hard water will cause respiratory distress until the cells have adjusted to the different osmotic pressure. Moving a fish from very hard water to very soft water will cause gill cells to explode. Areas such as the African Rift lakes and brackish coastlines are hard water environments. Generally, fish which prosper in these conditions are livebearers, some lake fish, Goldfish and brackish water fish. Rivers and riverfed lakes are typically soft-water environments (snow and rain water are soft water, lacking minerals). Many fish will prosper in these conditions. Note that fish cannot survive in water which is completely devoid of minerals (ie: RO or DI water).
ACIDITY & ALKALINE (PH)
Measured on a logarithmic scale, neutral water is defined as 7.0pH. Anything below 7.0 is defined as acidic, and above 7.0 as alkaline. A pH of 6.0 is ten times more acidic than 7.0 pH. Fish generally come from a pH range of 6.8 to 8.4pH, with several species coming from even greater extremes. Ideally, small fish should not be exposed to more than a 0.25pH change per day, while larger fish will tolerate 0.5pH per day. The ability of a fish to adapt to changes depends a lot on its size and condition.
AMMONIA (NH3) OR AMMONIUM (NH4)
In neutral to acidic water, ammonia (which is toxic) slowly converts to ammonium (which is not toxic). Plants & bacteria do not distinguish between the two, and consume either, but in extreme pH conditions, plants and bacteria will stop working. There are many subspecies of bacteria, but the type commonly associated with converting NH3/4 to NO2 (Nitrosomonas) prefers a pH of 7.8 to 8.0 and is inhibited at about 6.5pH. Nitrobacter and/or Nitrospira are commonly associated with converting NO2 to NO3 and nitrobacter is inhibited at 6.0pH.
The points for an aquarist to be aware of are: 1) your efforts to keep a healthy population of good bacteria get defeated when your pH drops too low, 2) while it's in its non-toxic ammonium state, the fish are not generally in immediate danger, however a large water change can raise the pH enough, so that the NH4 quickly becomes toxic NH3 killing the fish (either use many small water changes progressively, or chemically lock the ammonium down such that it stays non-toxic (ie: Ammo-lock)). A pH crash (also known as old-tank syndrome), results in low pH and high NH4, and is usually the result of poor tank maintenance, or too low a buffer.
BUFFER (kH)
German for Karbonate Hardness, also known as temporary hardness, buffer or alkalinity. Measured in ppm or degrees (divide ppm by 17.9), aquarists usually refer to how many degrees of buffer they have (dkH). Water with a low buffer is more susceptible to problems with pH instability. Any pressure on the pH, either from materials decaying (acidifying, causing the pH to drop), or from rocks leeching (adding calcium carbonates causing the pH to rise) will be more effective when the buffer is low. This can have undesirable effects in the normal routine of materials decaying (fish waste, dead plant matter, uneaten food etc). It is recommended to keep your buffer above 4dkH, and to be careful if your source water is normally below 4dkH. The effect of acidification it to consume the buffer, before affecting the pH, so as soon as the buffer is zero, pH swings will occur. While baking soda will boost kH without significantly affecting gH, the usual treatments for low buffer are to do more water changes, gravel vacuum more and add calcium carbonate leeching stones into the tank or filter.
RO & DI WATER
Reverse Osmosis and Distilled water are devoid of minerals (no gH or kH) so they are extremely unstable and unsuitable for fish on their own. To use in aquariums, minerals or other water (with minerals) must be added. RO or DI are useful when you wish to blend your own mix, as they provide a blank 'canvas' to start with.
RAINWATER & SNOW
Essentially pure mineral-free water, these have similar properties to RO & DI, though not as pure. Precipitation collects particles from the air (pollutants) as well as minerals as they contact the ground (roofs, rain-gutters etc). They can be an inexpensive but laborious method to obtain free soft water.
CITY WATER
May be soft water (ie: rivers), or neutral (ie: some lakes) or hard water (ie: wells). City water (or municipal supply) is typically brought into a water treatment plant where it is made safe for human consumption, by killing all organisms (ie: using chlorine or chloramines), and then the water is typically made alkaline (ie: adding caustic soda) so it does not deteriorate the city's plumbing infrastructure (acidic water oxidizes metal pipes). If you are on municipal supply, you need to find out if they use chlorine or chloramine. Chlorine is easily removed with a de-chlorinator or it can be left to evaporate (takes about 24 hours with aeration). Chloramine does not evaporate easily and it must be removed with a de-chlorinator (typically a double dose). Failure to remove chlorine or chloramines will cause damage to the fish's gills and to any bacteria (including the good bacteria colonies in your filter). Soft water is typically somewhat acidic (having a pH of less than 7.0) at source, but after municipal treatment, it will typically be much higher (ie: 7.0 to 8.0pH).
WELL WATER
May be soft (ie: some artesian wells) but more typically it is hard water, with a mixture of dissolved minerals and metals. Hard water is typically alkaline (having a pH greater than 7.0).
CO2 CHARGED
Most commonly affecting well water (and the deeper the well, the worst it is), CO2 charged water will have more gases dissolved in it, than would be there after being 'aired' out for a day. Putting fish directly into CO2 charged water will cause them stress as they try to equalize internally with the extra gases, and then as the extra gases dissipate, the fish get stressed in reverse (similar to diver's bends). To determine if your water is CO2 charged, measure the pH immediately after pouring a glass of water, and then again after the water has been left to air for about 1 day. Any pH difference is due to the CO2 changing.
CO2 INJECTION
Here the aquarist is deliberately injecting CO2 into the water, to promote plant growth. CO2, kH and pH are inter-related. With kH as a constant, increasing your CO2 levels (forming carbonic acid) will cause your pH to drop. The higher your kH, the smaller the effect will be of the CO2 (and the pH). It is desirable to keep any pH changes gradual and as stable as possible, throughout any process.
SALT
Can be naturally occurring (sodium chloride) typically in hard well water. Aquarium salt is often used for medicinal purposes. Typical salt dosage is 1 tablespoon per 5 US gallons, when you know you have no salt-intolerant fish (typically scaleless fishes, and Otos, Plecos, Corys etc). Marine salt also contains calcium carbonates to harden water. Water from a water softener is an unusual mixture to a fish. Water softeners are typically used with hard alkaline well water. The softeners typically use an ion exchange which replaces calcium with salt, leaving you with salty 'soft' alkaline water (a mixture which does not exist in nature, and is not really 'soft' to a fish). Provided the fish are not stressed by changing parameters, many fish will adapt to softener water, however several will not, so your results will vary.
TO SOFTEN & ACIDIFY
It may be desirable to naturally soften your water and add some tannic acids (almost essential for breeding some species). Driftwood, peat moss, Terbang and Oak leaves are all commonly used for this purpose. Recipe depends on material being used.
There are chemical means to acidify water (highly acidic solutions). Chemical methods have a tendency to either produce no pH changes (while exhausting the buffer) or cause a very significant pH drop (after buffer has been exhausted). For this reason, chemical methods should only be used in storage containers (or aquariums without fish) while slower natural methods can be used in the aquarium with fish (with some monitoring).
TO HARDEN AND MAKE ALKALINE
Details are covered in my page on rockwork. There are many minerals which will harden your water and increase your buffer. Some even affect only gH, leaving kH alone (Utah Ice). Chemical means exist to achieve significant changes in gH, kH and pH, but are normally used in water prior to being added to the aquarium (so the stabilized recipe can be verified).
|
