How to clean a fresh water aquarium quickly and efficiently

Updated 30th March 2012

Cleaning an aquarium without tears

Many people love to have an aquarium in their house. More than half of those with an aquarium hate the cleaning process. That is why after much enthusiasm at the beginning, it is usual to see an aquarium that has turned green (if the light is too much) or brown (if the lighting is poor) with the fish causing a small storm whenever they swim close to the gravel. This need not be the case. I believe strongly that the water in the aquarium should be so crystal clear that in the absence of another source of water one could readily fill a glass and drink it. Honestly! If you wouldn’t touch it with your tongue, then your fish should not be living in it.

The process I will describe assumes that you have an under-gravel filter, which is my favourite. In case you have another kind, you may find a way to adapt the method to any other filtration system.

Caution with electrical gadgets

Before you start handling water, switch off the pump and any other electrically operated gadgets in your aquarium. People who have winters use heaters for tropical fish and remove these gadgets completely from wet areas.

To change 20% of the water, leave 20% in the tank

Do not make a habit of changing more than 20 % of the water. The fish will hate you for udjusting their climate too drastically. To estimate 20% of the water, measure the distance from the top water level to the gravel surface and divide by five. Put a mark with a felt pen or tape on the lower fifth, above the gravel. All the water from the surface of the gravel to the mark is 20% of all the water in the tank and this is the water you want to throw out. This is an estimate really because the gravel is soaked in water, but we are assuming here that this is a negligible amount. All the water above that mark is 80% and you do not want to change it. How do you remove the lower 20% and leave the upper 80%? Remove it. Syphon some of the top water into a bucket, then remove the fish and drop them into the backet. Syphon the rest into the bucket with the fish and leave your 20% of unwanted water in the tank. You must do this operation as fast and gently as you can without stirring the dirt too much. You want the fish to be in 80% crystal clear water in the bucket for now.

Last out first in

Put the plants, stones and ornaments in reverse order. Anchor the plants properly and arrange the rocks and ornaments to bring out all the beauty in them. Put the fish in and follow them with the rest of the water, the 80%. Remember you have not put fresh water yet. You have only cleaned the gravel and thrown out the dirty 20%.

Chlorine is not good for the fish’s gills

Now the fresh 20%. It needs to be really fresh and not too different as far as temperature is concerned. It shouldn’t have chlorine either. Most cities add chlorine to kill germs in public water systems. There are three ways of removing chlorine:

1. Allow the water to just sit in an open bucket for three to four days. Chlorine turns into gas and escapes.

2. Boil the water and let it cool. Chlorine escapes when heated.

3. Buy a ‘Dechlorinating’ agent from your pet store – put the drops recommended per gallon and the chlorine escapes.

I prefer the first option though I have used all the three methods in different circimstances. If the water has been sitting in the same house as the fish tank, it will also be more or less the same temperature as the water in the tank. Fish do not like too big a change in temperatures very suddenly. It is okay if the temperature change is gradual.

If you use the second option, you will need to let the water sit before use so that the temperatures of the newly dechlorinated water and that in the fish tank can equalize. That could take a while. One way to make the fish acclimatise to water that is a different temperature is to put the fish in a polythene bag with its old water, seal the bag and then float it on the surface of the new water. The temperatures in the paper bag and those out of the paper bag will soon equalise and the fish can be released.

Now that you have a clean tank in thirty minutes or so, look forward to the next cleaning process after 14 days. Stick to this rhythm and you will get better and more efficient with time.

Clean the gravel with the 20% disposable water

Remove all the plants, ornaments and rocks and put them in another container. Now you are ready to clean the gravel. Agitate the gravel by stirring it up and moving it from left, and then to the right. Your objective is to get all the fish waste, filtered dirt and leftover food suspended in the water. When the water has all it can take, push the gravel to the left, or right and pile it high. All this time you are making sure that your under-gravel filter is not moved up or damaged. Under-gravel filters should not have gravel under them, so if this happens you will have to empty the tank and reset. This you do not want to do, so be careful as it will take you a long time. Once you have all the water out, pour some rinsing water and repeat the process. Remove this rinsing water and push back the gravel to its natural level.

If you have plastic plants, clean them with a soft brush. If the stones have a lot of algae, clean them with a course brush. If they do not look dirty, clean them anyway.

Next, clean the inside of the tank with a fabric. There will always be some form of slimy algae even if not very conspicuously. Clean the outside of the tank as well. Now you are ready to put back the residents. But before you put them back, clean the glass cover on the inside and put back half the water by pouring it on this slanting glass. This will control the stirring up of the gravel. You can also put a bowl on the gravel and pour the water into it to absorb the shock.

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Comments 2 comments

Emmanuel Kariuki profile image

Emmanuel Kariuki 4 years ago from Nairobi, Kenya Author


Pole about the shrimp. Is your tank a marine aquarium? The fresh water ones are Crayfish and also eat plants.

All publishers will publish a christian theme if it suits their programmes. Even Uzima press that used to specialize in Christian publications seems to have widened their scope. Contact EAEP (East African Educational Publishers) and Focus Publishers as a start.

Eunice Stuhlhofer profile image

Eunice Stuhlhofer 4 years ago

useful information. At the moment, I have a different problem caused by a shrimp in the fish tank. Without useful info from the sellers, the shrimp has caused chaos to the plants, stones and eaten fishes. Now we had to get a separate tank for it.

On a different note, I am writing a novel with a christian theme and was wondering if you know of any publishers in Kenya that I could contact.

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