100 gallon fish pond. 32x24x12 GB with gravel. Fill time 5 minutes 45 seconds. Drain time 1 minute 43 seconds.
Ammonia 0
Nitrite < 1 ppm
Nitrate > 80 ppm
PH 7.0
Plants show very slow growth but pepper has a bud on it. Lots of ants and metallic green flies.

Tub sitting in tank top inside has approximately same parameters but explosive growth.

Have not seen any aphids or any other insect other than those listed.

Obviously something is wrong and since my knowledge currently leans toward fish.............
HELP!