The dreaded cloudy water… it’s a common problem.
Aquarium water may turn cloudy for a variety of reasons (most of which are interrelated).
In this Aquarium Care FAQ article, I’ll talk about cloudy water syndrome in brand new fish-tanks (ones that may not even have fish in them yet).
The cloudy “stuff” in newly set up aquariums is most likely a precipitate. In the home aquarium, a precipitate forms in the following way.
So, brace yourself for a brief chemistry lesson. I’ll try to make it as painless as possible:
A precipitate forms when your aquarium water is supersaturated with a compound. Water can only hold a certain amount of dissolved minerals (think of it as a balancing act), and when your aquarium water is very hard, it may lead to the formation of a precipitate (the stuff that makes your water look cloudy). In other words, the water becomes cloudy when there are so many minerals in your aquarium that they can no longer dissolve in the water, and, hence, appear in an undissolved form. This undissolved mass of tiny mineral particles appears to the naked eye as cloudy water.
Well, if your aquarium suffers from cloudy water, your water is likely to be very hard. If you test your tap-water for hardness with a standard test kit, I’ll bet that you’ll find that it is, indeed, very hard.
1) Add RO (reverse osmosis water) which is pure H2O and which, therefore, has no dissolved minerals in it (see this Aquarium Care FAQ article for more information on RO water).
2) Wait it out until the water clears by itself, by re-establishes that chemical balance.
Most people just wait it out and the problem goes away (…at least, until they do a water change).
Option number 2, however, does not alleviate the hard water issue, a problem that may affect the health of your tropical fish (depending on what type of fish you want to get).
Also, the type of rocks, gravel, and/or driftwood you add to your aquarium influences the chemical make-up of your aquarium water (see this Aquarium Care 101 article). In fact, some types of rocks and gravel may release more minerals into your tank, making the hard aquarium water issue worse.
So, the cloudy water situation is usually a reliable sign of a much bigger problem – very hard aquarium water caused either by poor tap-water quality, or by the addition of mineral releasing rocks and gravel into the fish-tank, or by both!