It's not really a constant fix regarding the water levels. The tank is covered and evaporation is minimal. I add maybe a cup of water to the 5 gallon tank every week. As the 4 plants grow, I'm sure they will draw more water
There is a cycled gravel bed in the tank containing bacteria to break down the waste from the snails and the shrimp. The 14" bubbler runs down the center of the tank along the base that forms a bubble curtain driving water flow from the bottom to the top along the entire length of the tank.
Another plus working for me is that in addition to the rams horn snails there are these little burrowing cornucopia snails that I have in the gravel. When I feed the tank, they come to the surface and end up churning the gravel.
So there is a pretty good bio load of inverts in the tank producing waste. I think the biggest trick will be balancing that load with the available bacteria in the tank to produce an adequate amount of food for the plants.
So far the plants are growing very well with very rapid root growth extending into the tank from the net pots. We'll see how it progresses over the next few months.