I am trying to figure out if my system is cycled and what else I need to do if anything. I live in Florida. I have had my indoor 30 gallon system with 6 goldfish for about 5 months with pretty much only an aloe plant growing in it. The fish have been in there the entire time. Below are the most recent readings.

I am confused as to why my nitrate levels don't stay up. If it's cycled okay, i can't imagine that the single aloe plant has been using up all of the nitrates. On the other hand, if it isn't cycled, I don't know why the ammonia levels haven't really increased. Thoughts?

Date             pH            Nitrate            Nitrite              Ammonia

Jan 10th*      8.0               0                    0                      .25          

Jan 14th**     6.4               0                    0                      .25

Jan 21st       6.4               160                5                       4

Jan 23rd       6.4               160                5                        1

Jan 28th       6.4               0                    0                       .25

* After reading, added 1.5 cups of aquadown. Needless to say, it ended up being too much

**After reading, added soluble fertilizer. A tablespoon daily. I'm not entirely sure what it is. A fellow aquaponics user gave me a small bag of blue and white powder to mix with water. Added a tablespoon in a 1.5 liters daily until the 21st when I took the next reading.