January 2015 Indoor Aquaponics System

[Richard Kowalski]

My growing season ended in October when we had a cold snap and my plants were wiped out. My tilapia were not at a harvestable size yet and the water temperature dropped to 58F. 

I built a indoor Aquaponics System based around a 100 Gallon Cattle Trough. I had very little space in my basement, so the entire system needed to fit on top of the fish tank.

I had a 30 Gallon storage bin that I used for the grow bed. I used the hydroton from the outdoor system, which already had the bacteria nessesary for converting fish waste. The system cycled up quickly and the fish are happy in their new home.

The first problem I have with this system is that the time it takes for a a complete flood and drain cycle is 4 minutes. I am afraid that the roots of the plants will be too wet. I planted Beans, Basil, Spinach and Romaine lettuce. The Bean plants took off. But the rest of the plants are growing slowly and then dieing off. I am guessing that it is root rot. When I examine the plants after they die the roots are under developed and the plant stem right next to the roots is mushy.

The next problem I have is that the Nitrate levels have been off the charts since the beginning of the system. I am feeding my fish once a day. The plants are showing signs of mineral deficiency. I have been adding Calcium, Potassium, Chelated Iron, Maxi Crop, Worm Casting tea and Epsom Salt at different intervals with little effect. I also have worms living in the grow bed. Its a constant battle. I built a Grow Tower to try to add more plants to the system and also to see if I can make the roots of the plants dryer in the tower, they might grow better. More plants means lower Nitrates also. The tower has been running for a few days now so its hard to tell if it is working yet. I also ordered some Duck Weed to put in the Fish Tank to sop up some more of the Nitrates.

I have been harvesting Beans every couple of weeks, but nothing too earth shattering.

These are the things I am working to resolve. Its a learning process.

[Luana Hiebert]

We had a very similar problem with a larger system in a greenhouse last summer. We have decided that the reason the bell siphons were cycling so fast was that they were not straight up and down. We are trying to rectify that. Don't know if that helps any, but I do know that too fast fill and drain can lead to the problems you describe.