This is my current tank, which I don't particularly like the layout of and the substrate is breaking down and making my tank dirty. So after my new setup is ready in the next few weeks, I can transfer the inhabitants (betta, shrimp and snails) temporarily into that whilst I redo my 28l tank.

Substrate

I was considering ADA aquasoil as I've heard it's good and is relatively small so would suit a small tank. There's various options; I was thinking Amazonia would be a better colour, but the Malaya sounds like it will last longer. Other than that there's Ecocomplete, but I think the grains will be too large for the tank and the bag size might be too big and therefore be wasteful. I used fluval stratum for this tank and I think it's that which is now breaking down and making the tank dirty.

Layout

I have a couple of nice stones which I was thinking of arranging something like this (different angle) on a slope. Ignore the small flat stone at the front, it's propping the other one up. I ordered a red tiger lotus plant and would have to fit that in somewhere. I was considering a sand path through the middle, like this. I can decide properly on the final layout later, but if I want a sand path I need to decide sooner rather than later. Am I going to have issues with it getting dirty?

Filter

I definitely want an external filter. I have the ocellaris 400 on my current tank, which is a good size although I don't know if it will be too much for my 28l. Previous suggestions have included the eheim 2211 and eden 201 (although Id need to check if Id be able to hang it on my tank as it has a lid).

Lighting

It's a PL bulb in a set fixture in the tank lid, which I don't think I can do anything with. The type I buy is meant to be for plants.

Plants

Haven't thought too much but I definitely want things which I can keep small and in control. Im not sure where the red lotus will come into it but I think I can keep that fairly small? If not it could go in my larger tank. I was thinking dwarf hairgrass, so the shrimp have somewhere to hide. Not sure what else yet.

CO2, ferts etc

I have a liquid CO2 Im using at the moment although its not brilliant, and a liquid fertilizer. I have a bottle of flourish excel that I haven't started yet - does that take the place of CO2 and ferts or just CO2? I have a CO2 bottle on my larger tank, so have the potential to split the line but I'd rather not do that until I've mastered using it properly on the larger tank. Plus as I don't have brilliant lighting, I might be best without it.

Feel like I'm missing something but I think these are the main decisions at the moment.