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My cherry tomato certainly seems to be growing faster in the aquaponics setup than the tomatoes that I have planted in dirt. I don't know if I have enough fish in the tank to produce the amount of nutrients necessary for several tomato plants, they can suck up a lot of nutrients.

Yeah if all that's in your pond is a few goldfish you might want to supplement. I think I will have to supplement this year due to losing a few large koi last fall, I hope by using organic foliar feed I can avoid nitrite spikes in the pond. I always supplement iron in the aquaponics, I strongly recommend putting an old piece of iron somewhere in your tank to slowly rust and dissolve.

A piece of iron in the water sounds like a good idea. I'll have to try that.