Welcome to the forum! In general most fruits and vegetables take nutrients well in a given pH range, say 6 to 7.5 give or take. With respect to nutrients it's more of a buffet for the plants - trying to keep adequate nutrients in all areas and the individual plants can absorb what they need / like. It is usually very unlikely that you will have such an excess of one nutrient that negatively affect plant growth, though nutrient deficiencies are common - especially iron, but also calcium and a few others.

With a starting system you are more likely to have nitrates and be light on other nutrients, so leafy greens are a good start. But as your system ages, your fish feed rate increases, and you add supplemental iron and maybe trace minerals if needed, you will support a wide variety of plants in a favorable pH range. Some are very successful with pH into the low 8's.

Thanks, dstjohn99, that's very useful info!

If I want to have a system with decorative fish (I don't want to kill fish) and a variety of plants (potatoes, carrots, onions, tomatoes, cucumbers, peppers, greens, lettuce, peas, and I somehow manage to get EC about 1.8 and ph of about 6.5-7, would you think it would be a balanced system?

I realize I need to take a very well-paced approach on this, starting off in smaller portions, gradually filling up the tank and the growbeds but in theoretically I could get to such a stage. If I then put a filter system either in the beginning of irrigation of in the end, to monitor and control EC, ph, flow, etc., would that work?

Of course, I would need to have a very well calculated fish tank, growbed infrastructure (containers, root area, irrigation tubes, sprinklers, mist makers, etc..) and a very well timed water pump.

I'm planning to build a family year-round plant-based diet greenhouse, powered by solar panels, rainwater harvested water, and aquaponics system. Each plant will be grown in a specific container to best utilize its specific growth characteristics. That would involve using different watering methods but I plan to mostly use aeroponics (both high and low pressure systems, depending on the desired root growth) in vertical growbed "towers". I would also have to think about aeration of the water somehow as well as adding CO2 in the most eco-friendly way (so far I've found various types of fermentation to be the safest bet but I'm still unsure about those)

A side question on the fish tank: how to deal with fish waste and dead fish? Does the bacteria on the tank bottom take care of that?