Reviewing this thread, I noticed something that was bothering me. In the pics, the tank looks much shorter than it is, and the filters in the back look huge. The camera is distorting it, especially on the frontal pics, I think it is because I need to take the pictures from a short distance since it is in a small room, and it uses some sort of wide angular lens or effect. In truth, each filter is 15cm wide and the free area between them is 50cm long, adding up to the 80cm total length.
I removed the sapucaia to keep the water color under control. I also did a water change and it cleared a bit, maybe a bit too much. I moved the sapucaia to my water change reservoir, so the fresh water will come painted. I'll do a water change tomorrow and see how that works.
The good news are that I found a fish store in the other side of town who announced tukano tetras. So after a small journey, I now have 12 tukanos. I had established that when I found the planned fishes I would remove the rummy noses, and that day has finally arrived. Removing fishes from tanks is among the most frustrating aspects of the hobby for me, and this time it wasn't any different. In any case, it is done and, after 40 minutes, the 3 rummy noses are now swimming in a large school in the main tank.
No quarantine for the tukanos, and I won't do it for the other fishes as well. I'm suspicious of my quarantine tank, and all these small fishes look particularly fragile, so I'm thinking that less moving around is for the best. And I'll take my chances with possible diseases.
The bad news is that a cyano infestation started. It is still just starting, but I'm not one to underestimate cyanos. I thought that the low light levels would stop algae from bothering me, but the cyanos are forming at the surface and on the wood closest to the light. I have once again covered the lights with the kitchen paper towel and I'll siphon as much detritus as I can. Some of the leaves deteriorated very fast... I won't be using those anymore. Floating plants won't help, the cyanos are growing on and around them.
I'm considering some sort of background for the tank. I want to add a layer of polystyrene to the back to help keep heating expenses down, but for that I first need to find a way to hide it. I've never done anything bolder than all-black backgrounds, I'll try and ask around at print shops if they have affordable options. I'm thinking some sort of degrade from black to white moving from the bottom and from the sides to the top center, forming sort of a white half ellipse. The yellow water would make the tones go brown/yellow. I like the soft degrade that formed naturally with the tank light illuminating the wall behind the tank, but I want something that hides the filters on the sides.