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Fixing A Green Tinted Fish Tank - Murky Water Solutions

Everyday Green had a problem with green tinted water in a home aquarium just over two years ago. This was the winning solution!

Green Tinted Aquarium Solution

What is a long term solution to a green tinted fish tank? Especially one that doesn't seem to have and obvious cause (IE. excessive fish waste, infrequent water changes, algae growth on the interior tank walls). This is a problem that many seasoned tank keepers run into. The cause is almost always a mid range level of nitrates in the water that lead to diatom growth. While the diatoms are predominately green, on occasion and dependent on strain, there can also be brown and combination yellow tints seen in the water. Mind you, this is a tint, sometimes even so faint that you get used to seeing it and don't realize that your water is no longer the pristine crystal clear it used to be. Let's get you back to viewing your pets in the vivid way you used to at the beginning.

Green Tinted Aquarium Water

Day 2 of Treatment

Day 2 of Treatment

Step 1 – Diagnosing the Cause of Green Tinted Water

Green tint in aquarium water comes from one of two sources, dying live vegetation or microscopic algae blooms. One is easily visually detected. The other can be diagnosed with a simple water test kit that tests for ammonia, nitrite and nitrate. The key here is the nitrate level. Most established aquariums have a sufficiently developed bacterial system to process bot ammonia and nitrite wastes. In cases of high ammonia and nitrite there will be additional concerns in your tank – fish laboring to breathe, unexpected fish deaths, disease appearance and the like. These two components are not the problem in a green tinted aquarium.


The issue likely lies solely in the nitrates, the basic food that your algae bloom is feeding on. This is doubly probable if you don't have a live planted aquarium to help filter them out. Most water test kits come with either a dip strip or color changing solution dropper. In either case there is a color coded index to compare your water to. A level of nitrate between 5ppm and 10ppm is the goal. 20ppm to 50ppm is the range where an algae bloom will arise. Above 50ppm and your fish will start to suffer from poor water conditions.


Step 2 – Treatment of Green Tint and Murky Water

The short term solution to an algae bloom is tempting. There are plenty of chemical solutions for hobbyists. Unfortunately these are not the best solution for your fish or your tank. Fast changes in water conditions, like total nitrate elimination through liquid chemicals, can cause undue stress on fish that are already compromised. In trying to make your tank aesthetically pleasing, you may very well kill your pets! Instead of massively dosing your tank right away, slowly reduce the nitrate levels through a combination of 25% water changes and physical filtration through resin media. Aim to reduce the nitrate levels around 10ppm per day until they reach the acceptable range.

Step 3 – Future Prevention of Diatomic Algae Blooms and Tinted Water Problems

Once the aquarium has sparkling clear water again, how can it be maintained? There are two methods that can be used separately or in tandem (usually with the best results), nitrate removing resin media and submersible UV light sterilizers.


Nitrate removing resin media added to an over the side or canister power filter is the most popular and cheaper of the two alternatives. Resin media packets are rechargeable and can be found rather easily online. Most large pet store chains do not carry them in store for some reason. Fluval and API make reasonably inexpensive self contained inserts.

Submersible UV sterilizers are an exceptional, but expensive, choice. They are very effective at killing off an algae bloom and preventing a recurrence as well as destroying other fish tank pests including bacteria and parasites such as gill flukes and Ichthyophthirius Multifilis

(ich). The biggest issue with using this piece of equipment alone is that it will mask one of the signs of a nitrate problem in your tank by preventing the algae bloom.



UV Aquarium Filter

Maintaining Crystal Clear Aquarium Water

The obvious long term solution to maintain crystal clear aquarium water is to use the dual method of resin media with a UV sterilization filtration system. Employing this method will not eliminate the need for proper tank maintenance, but it will significantly improve the health and lifespan of your fish friends and prevent unwanted stress (to both you and them).


The use of the dual solution might even significantly reduce the number of water changes you have to do during a month – but that will all depend on your fish and plant population. Whichever method you choose, happy healthy, high definition viewing is in your future for years to come!


Crystal Clear After

Crystal Clear Water

Crystal Clear Water

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Everyday Green

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