WATER
My Golden rule:-
'Crystal clear water' doesn't necessarly mean fish will live in it.
Vodka’s clear, but fish won't live in it!
I tend now to use a mixture of rain water and R.O. (reverse osmosis) water as the water companies in my locality tend to use a considerable amount of chemicals to keep the main supply safe for human consumption. Unfortuneately some of these chemicals can have a detrimental affect on the health of ones fish, especially with more delicate and sensitive species; However, when I am forced to use ‘tap water’ I always use a declorinator.
Buy test kits, (pH, Nitrate, Nitrite, Ammonia & GH); the LFS are not usually open at night, which is usually the case when we spot that something is amiss after arriving home after a hard days work.
There are plenty to chose from, individual tests, master test kits and all-in-one test strips. Also try testing your mains water from time to time. Test it once as it comes out of the tap; then, leave a cup of tap water for 24 hrs, and then test it again. As well as knowing the chemistry of what you are starting with Sometimes the pH may drop, as certain additives that water companies put in their water to 'buffer' the pH to neutral, deteriorate. If this happens you are now aware that this could affect the pH in the aquarium a day or so after you carry out water changes. Also on occasion the tap water in my area has proved to contain both Nitrates & Nitrites. All these things can and will cause problems to your fish, armed with this knowledge corrective measures can be taken when the need arises.