IMy longest running tank using this method was 14 month due to needing to repurpose the tank, but with LOTS of heavy root feeders, I believe it's possible. The detritus buildup in the sand was pretty minimal considering over a year of overfeeding and not vacuuming. HOWEVER, the tank would need to be "lighly" stocked. You will need a huge tank. My maintenance for the tank was 50% weekly water changes and I would use a turkey baster to stur up any detritus buildup to remove it from the water column. This step is crucial and may be more than you are looking for. You also need a jungle of plants.
To do a tank like this with big fish, I would recommend a sump where you grow a weed in the sump to remove any excess nutrients. You would need to setup the tank and plant it for a month or 2 before adding fish though. Stem plants are unlikely to stay put. Swords, bulbs, and crypts are going to need to be the bulk of the plant mass due to heavy root structures that are difficult to uproot once secure.
Floating plants can also work great for this depending on if you can keep the tops dry. Floating plants largely die off if their leaves get wet regularly. This means that glass and acrylic tops are difficult. Mesh is the alternative for a lid, but for a tank that size, humidity may be an issue.
One other note, if you have enough and the proper flow, much of the waste can be suspended in the water column and goes in your filter. This would help substantially with large fish.
Here is the tank I had up like this. Granted it was much smaller, a 20 gallon, but the principles are the same. The top down of the Crypts was just before I pulled the tank down.
To do a tank like this with big fish, I would recommend a sump where you grow a weed in the sump to remove any excess nutrients. You would need to setup the tank and plant it for a month or 2 before adding fish though. Stem plants are unlikely to stay put. Swords, bulbs, and crypts are going to need to be the bulk of the plant mass due to heavy root structures that are difficult to uproot once secure.
Floating plants can also work great for this depending on if you can keep the tops dry. Floating plants largely die off if their leaves get wet regularly. This means that glass and acrylic tops are difficult. Mesh is the alternative for a lid, but for a tank that size, humidity may be an issue.
One other note, if you have enough and the proper flow, much of the waste can be suspended in the water column and goes in your filter. This would help substantially with large fish.
Here is the tank I had up like this. Granted it was much smaller, a 20 gallon, but the principles are the same. The top down of the Crypts was just before I pulled the tank down.