Cloudy white water - bacterial bloom explained

A common situation that my customers face with new aquariums (and, of course in established aquariums) is bacterial blooms - the cause of cloudy white water in an aquarium.
In new and established aquariums this is the result of waste products being broken down by bacteria  and, a spike in ammonium following.

There can be many causes for this.... in a new aquarium it can be a result of excess nutrients in the water. This results in certain types bacteria multiplying in huge numbers to breakdown the waste causing a milky white effect in the water. The bacteria will eventually die off as a result of starvation when their nutrients in the water decrease i.e. there is less food for them to eat. An ammonium spike usually follows the appearance of this cloudy white water followed by the next group of bacteria that grow and breakdown the ammonium. Once the full cycle is complete i.e. ammonium --> nitrite --> nitrate you will notice that on your water test kit no longer registers ammonium or nitrite and, but registers nitrate in your water.

In cycled aquariums bacteria blooms can be caused by overfeeding or washing the aquarium filter with fresh tap water which contains chlorine - killing the colonies of established bacteria in your filter resulting in a reset of the bacterial cycle therefore, a bacterial bloom.

If this were to happen the best thing to do is to make sure your air stone is on full ball and your water surface agitation is at its maximum. Fish will usually survive this event in a freshwater tank.... but, probably not a saltwater tank. Its best to try to avoid resetting your aquarium cycle as this causes stress to your fish and often results in diseases such as white spot.

When first starting in the aquarium hobby (about 10 years ago) I went through the stress of bacterial blooms and associated ammonia spikes a number of times. At one stage I owned a 3 foot saltwater tank with a canister filter and about 10 kg's of live rock, a pyjama cod and a lion fish (although i had no idea about their ferocious eating habits - which I was unequipped for). As many new marine hobbyists do I fed them way too much and, as a result caused a bacterial bloom and a huge ammonium spike! Needless to say this killed both my fish ... due to my impatience..... the tank was only 1 month old and deciding to add these two hungry beasts into my aquarium was not a wise choice. The bacterial colonies in the tank and filter were not established yet.... well not enough to handle the these fish and their waste.

As if this experience wasn't enough I tried again i.e. got rid of these dead fish let the tank cycle again and, then added a few corals (not such a bad idea). However, I made the unwise choice of adding liquid coral food and more than likely overdosed the system. Next morning I woke to find that the aquarium had turned cloudy white again! and, that all the live rock had died off.... the tank had a putrid smell. Besides overfeeding.... in hindsight the canister filter probably wasn't the best choice for this aquarium.

When first starting in the hobby most people do not realise how much work is involved with setting up an freshwater or saltwater aquarium.

So more often than not bacterial blooms will resolve themselves however, 25% water changes don't hurt and, holding off of feeding your fish is probably a good idea also.

Dan

Nitrogen cycle explained

Nitrogen Cycle

The nitrogen cycle is a term used to explain the cycle that breaks down fish waste and other
types of waste into Nitrate, a process which occurs in your aquarium (fresh or saltwater).
When fish waste enters into the aquarium (i.e. Nitrogenous waste) it is quickly converted into
ammonium, a very toxic substance for fish. Bacteria which live in an aquarium have the job of
breaking this ammonium down into nitrite; another substance toxic to fish. The breakdown of
ammonium to nitrite requires oxygen and, the presence of Aerobic bacteria (i.e. bacteria which
require oxygen to survive). The final step in the cycle also requires oxygen and aerobic bacteria
to breakdown nitrite into nitrate, which is the least toxic of the substances in the cycle; this is a
substance which typically builds up in an aquarium which requires a water change to remove.
Fish can tolerate higher levels of nitrate however; this can also get too concentrated in an
aquarium and also cause fish to stress. High nitrate levels can compromise the immune/defence
systems of fish, and cause problems like white spot.

Usually ammonium or nitrite is present in an aquarium when it is first set up. Reason being, that
each step in the process requires different types of bacteria however, it takes a while for these
bacteria to colonize and grow in your filter and aquarium gravel/decor etc. Once these bacteria
have colonized the aquarium they will breakdown the ammonium and nitrite to nitrate very
efficiently so long as the fish are not overfed or overpopulated in the aquarium. It normally takes
about 2 -3 weeks for the cycle to establish in a freshwater aquarium (longer in a saltwater
aquarium). If ammonium or nitrite is detected in an aquarium after it has been established, it can
mean that the fish are being overfed, which in turn is causing the fish to create more waste than
the aquarium can handle. The following levels would be considered toxic to fish and other
animals in an aquarium:

Nitrogenous Compounds Concentration limit for an aquarium:

Ammonium 0.4 ppm
Nitrite 0.1 ppm
Nitrate 100 ppm
ppm = (parts per million)

*** When the concentration of nitrate reaches 50 ppm it is best to perform a 25% water change.
So what happens with the Nitrate?

Well, nitrate is actually broken down by anaerobic bacteria (bacteria which survive in an
environment containing NO oxygen). Due to the fact that most aquariums do not contain many
areas for the anaerobic bacteria to live, nitrate isn’t actually broken down very fast and tends to
build up in an aquarium, so water change is a must. Filters, when working correctly are quite
saturated with oxygen from the aquarium water therefore; do not typically contain these bacteria
either. In the wild, it’s a different story – there are many places for these types of bacteria to live
therefore the water quality will always be much better than what most aquarists can simulate in
an aquarium.

Filter

This is where the breakdown of the majority of waste happens. The explanation above details the
process that actually takes place inside the filter and, to a lesser extent in the actual aquarium, on
rocks, in gravel and on decor or plants. For this reason it is vital to never wash filter media with
tap water which contains chlorine, this will kill the bacteria in the filter. It is always best to wash
filter media with aquarium water, or only change the filter wool and leave the rest of the filter

Here fishy fishy

Just a couple of pictures of the 4X2X2 salt-water fish tank. The coralline algae are starting to grow all over the rocks and, even though the tank is bare in terms of corals I think this tank looks awesome.




So basically all water changes are done using pre-bought ocean water which has a constant salinity of 1.022/1.023. Interestingly enough water is only changed once a month however, this tank has been going for about 2/3 years so it has established quite a good bacterial colony in the filter media.



Mod's done to the filter include - removal of all plastic bio-balls (waste collectors and nitrate factories...in my opinion). Addition of matrix filtration - repaired protein skimmer which works a charm. The filter itself has quite a deep layer of course coral sand - probably a good nitrate reductor.



Tropic Marin trace elements added once weekly and fish fed 3-4 times week with spectrum, brine shrimp and algae wafers.

Here is some pictures: