Backyard Aquaponics
A place to discuss aquaponics

Ammonia and Nitrite should be 0.0ppm. If they aren't it means your system is not balanced, ie: insufficient bio-filtration (wet gravel) for the amount of fish.

Anywhere between 0.0ppm and 40.0ppm is fine for Nitrate, as long as the plants are growing well. It's possible to have 0.0ppm in readings and have good plant growth, it just means your system is well balanced and the plants are using the Nitrate as they are being produced.

If you think the plants could do with more nutrient you can try feeding your fish more, if they will take the extra feed. This will provide extra growth in the fish as well as more nutrient for the plants. Just keep an eye on the Ammonia level to ensure you aren't exceeding the systems bio-filtration capacity with the extra feed.

Thanks for that!

You don't want to be raising the nitrite levels, since nitrites are toxic to fish. Nitrate concentration is dependent on how many fish you have, how much you are feeding them, and how much the plants are using.