As the rest of our articles on pH maintenance have mentioned, measuring the pH of your aquarium is vital to keep your aquarium healthy. As you can see on the chart, water with a pH of four or less, or ten or high will kill your fish. Water with a pH of less then six will most likely kill off your plants and algae.
The optimum pH range your want to aim for are between 5.5 and 8.5, with freshwater fish preferring a slightly more acidic water [link to freshwater/saltwater aquarium article here] of 5.5 to 6.5 and marine or reef aquariums favor a more alkaline water from 7.5 to 8.5.
It is very important to test your water between once a week and once a month (two weeks is best) to make sure that it stays within the range you want. Always test your pH after a fish death or illness.
Good products for testing pH Level in your Aquarium Water
Use products such
and follow the instructions carefully.
Don’t forget to make sure that your pH testing strips are designed for either freshwater or saltwater aquariums, or will cover both types.
The benefit to water-specific strips is that they will have more accuracy within the preferred range of your fish and you will be able to fix ibalances faster than with a generic strip that has to cover a wide range of pH.
Regardless, you must follow the instructions on your chosen pH strips very carefully. It is also very important to test the pH levels at roughly the same time of day when you test them.
The pH of a tank will change depending on light cycle in your aquarium due to the nitrogen cycle we covered in this article [what causes High pH]. It’s also recommended to keep a log of your water pH so you can track patterns such as time of day and how the pH is affected by it.
If the variation is a slight one, say a from from 8.1 to 7.9 in a saltwater tank, you can choose to wait a week to see if it naturally balances itself out or if the pH continues increasing.
It is also important to check that your fish and plants’ preferred pH levels are close enough to keep them all satisfied. Here are just a few freshwater fish and their preferred pH levels, and as you can see, there’s quite a range to them.
Test your water before buying any new fish and ask what their pH range is to see if your habitat can keep them healthy.