Cycling a Fish Tank

Water Testing

The first hurdle has been passed as the ammonia is now down to about 0.25 ppm from a peak of 4 ppm. We're not out of the clear yet, the nitrite is somewhere between 2 and 5 ppm at the moment. The nitrite can be just as dangerous to the fish as the ammonia so it will be important to get the levels down as quickly as possible. 

The light at the end of the tunnel

The good news is that nitrifying bacteria are doing their job and the nitrate is on the rise. The aquatronics sensor system is showing me my slow uptick of nitrate.

It's great to see the system in process as the ecosystem is now ready to start supporting plants. I've been running the aquatronics sensors on 4 aquaponics systems for 6 months but this is only the second time I've been able to capture a tank in the cycling process. It's great to see everything is right in line with the API test kit, and there's nothing better than just opening your phone to check your nitrate instead of shaking the different bottles and test tube and running timers. 

First Steps in Tilapia Farming

Ordering the fish

My previous aquaponics systems have all run off of goldfish. They're easy to find, they produce a lot of waste, and they're pretty hardy. On my new system I'm looking to eat the fish I raise, so goldfish were no longer the natural choice. The most common fish for this application is tilapia, so I decided to go with what's known to work. I live in Connecticut and was looking for them locally but couldn't track any down. After searching around I found Allied Aqua who had great reviews. They had a number of strains of tilapia, and I went with blue tilapia. My tank is in the basement so I wanted a strain that would still grow well at lower temperatures and the blue tilapia are one of the hardier types that exhibit strong growth.

The shipping process

I've brought fish home from the pet store and it already seems traumatic enough for them, so I had no idea how it was going to be coming in from Missouri. They arrived in a styrofoam container with some insulation and a plastic bag on the inside. I had ordered 25 but around 35 ended up coming in. There is a slow acclimation process to get them adjusted to the tank water. They were all skiddish at first but now they are fully settled in.

Introducing them to their new home

In another post I'll go over how I got the tank water to begin the cycling process before adding the fish. They've been in the tank for two weeks and the water is almost cycled so they have definitely made it through the toughest part of their journey. The tank is 150 gallons and there's 35 of them so it will be tight if they all grow out to 1.5 pounds, but I'll be harvesting them in the process. Aquaponics does a great job of filtering the water so technically some people say 1 pound of fish per 3 gallons of water is feasible but it's really pushing the limit so I plan on keeping it closer to 1:5 at the most once all the fish are grown out. That's still six to nine months out so in the meantime they have plenty of space to call home.

Integrating Aquaponics Into Your Home

Initial Thoughts

Building an aquaponics system in your home is a great activity. Any DIYer can enjoy coming up with a design, going to Home Depot to get everything you need, and making your vision a reality. I've had a few desktop aquaponics systems in the past but recently I decided to make a system that could produce a significant amount of vegetables and fish. As an engineer I had all sorts of plans for a huge fish tank, red and blue LED grow lights hanging from the ceiling, and sprawling grow areas.

Reality Check

After conveying these ideas to my wife I quickly realized this was going to need to stay in the corner of the basement if things were going to go how I originally planned. Once we started brainstorming together the plan started taking a much more exciting route. Luckily there was a middle ground between maximum food production and an aesthetically pleasing home garden. For instance, we could have a pleasant garden in our kitchen:

But at the same time focus on maximizing fish production in the basement:


This split level system was able to meet both our requirements. The water from the basement is pumped up to the first floor, and then there's a T with a ball valve for expanding more grow beds in the basement when we're ready. That way if I want my red and blue LEDs everywhere for a night club looking grow space I don't have to burn the retinas of any tolerant guests. My wife and brother-in-law both had great ideas for this system and I was very happy to follow their guidance. We're looking forward to producing both vegetables and tilapia out of this system, and can't wait to see how things progress!