Opening an aquarium has been such a wild ride with so many moving parts and hard work. I want to share the basics of water quality and what goes into maintaining it daily to make the healthiest environment for our fish. Many people might think water quality is boring, but it’s a very key component of fish keeping and a BIG part of being an aquarist.

water quality vials

Let’s cover the basics before I get to some cool stories. The nitrogen cycle is what we measure in the lab when we are testing our water quality. Fish waste and excess food will create ammonia, and then Nitrosomonas bacteria will turn the ammonia into nitrite. Nitrobacter bacteria will then turn the nitrite into nitrate. And we can remove nitrates from aquaria with water changes, live plants, or certain types of filtration.

The “good” bacteria in the water is what drives the nitrogen cycle and we want to keep those bacteria happy because they keep the water clean for our fish. We test the levels of ammonia, nitrite, and nitrate in the water in our lab on-site. Ideally, the results would be zero for all of them, but when it’s slightly elevated we can respond appropriately to keep the health of the exhibit.

nitrogen cycle

You’ve probably heard about “cycling a tank” before you can put fish in it, and that refers to culturing a healthy population of these bacteria that can handle the number of bacteria that the future residents will be putting into the water. Now imagine cycling an entirely new aquarium that has just been built with close to half a million gallons of water in it.

aquarium tunnel picture

Every day we meticulously calculated how much ammonia we would need to add to the exhibits to “feed” the bacteria. The goal is to eventually be able to add the same amount of bacteria that we calculate the fish will add to the system and slowly culture the number of bacteria needed to handle that organic load. I carried many 55lb bags of various chemical compounds and weighed out specific amounts to add to our exhibits every day based on our calculations. It was a lot of hard work on such a large scale.

Next time you’re in math class or chemistry class and you think to yourself, “I’m never going to use this,” let me tell you, if you want to care for animals in an aquarium, you most definitely will. I was not a perfect student, I failed my chemistry class in college and had to retake it. Then, after not using chemistry for many years, I had to rapidly get familiar with it again since our bacteria cycling project was happening very quickly.

Dani Jensen in a hard hat

It was a joyous day when we did our water quality testing and realized our new large exhibits were completely cycled and ready for fish. Seeing the first fish get released into our Grand Aquarium brought tears to my eyes as I had worked so many long hours to get everything prepared for them. Our finished aquarium is such a beautiful site with so many species and amazing artistry. Hope to see you all visit soon!

Dani Jensen aquarium exhibit