To set up a planted aquarium is very similar to a regular freshwater aquarium but the plants are going to need very bright lights and when you have bright lights in the tank to promote photosynthesis you're also going to get a lot of undesirable algae. So it's a balancing act between having just enough fertilizer and nutrients in the water, preferably where the root systems are so you want the nutrients in the gravel bed for the plants, and you don't want to have too many excess nutrients where your algae's growing out of control.
You need bright lights so you can't really have lighting be the limiting factor to control algae growth so basically you want to have a very, very good gravel bed substrate that's ideal for growing plants like SeaChem's fractured clay. It's a reddish clay but it's perfect for the root environment. And there's a lot of Amano-style, Aquarium Design Group sells some stuff that's perfect for keeping live plants.
You also want to make sure your phosphates and your nitrates are kept in check. You want to do big, big water changes, more than a regular freshwater aquarium. Most plant enthusiasts will recommend doing an 80-90 percent water change once a week with reverse-osmosis. deionized water so you're not introducing a lot of nutrients. And you want to make sure the pH is very stable for your planted aquarium.
The best luck I've seen is when you have a canister filter, you feed very, very sparingly, only have a few fish in the tank and change 70-80 percent of the water once a week with good reverse osmosis deionized water with the same matched pH. That's going to prevent waste from building up in the water column. Your ammonium nitrite should be perfect. Your nitrates and phosphates should stay low because you're changing 80-90 percent of the water and your substrate is going to have just enough nutrients in there to promote good, healthy root growth and all the minerals that are staying in the gravel bed are going to also - from that good gravel that you've bought - is going to help support good, healthy, strong roots.
And then you'll want to prune your plants. They're going to grow. When you set up a tank, you're going to have a design or a style in mind so you'll use taller plants in the back, short plants in the foreground. But as these plants grow, the look is going to change and pretty soon it's going to be grown, it's just going to grow out of control. So you want to constantly get in there and prune it and clip it and keep it like a well-manicured garden.
And don't overstock the aquarium. When you have too many fish they produce a lot of waste. As that waste settles on the leaves it's going to burn holes in the leaves. So you'll want strong flow, not too much but a little bit more than a regular fish-only aquarium and not a lot of fish. Remember the emphasis is on the plants. That's the needs of the aquarium for the plants not so much for the fish.