Don't be apologising. You're a fountain of positive encouragement and advice! I feel like I need spreadsheets at this point! You just read so much and it gets muddled. I don't like fish that harass others so really prefer a chill community tank, active but not aggro. I've the 58L tank too so this might be an option for shrimp or species only.
@AdoraBelle Dearheart do you've black sand in your Cory tank? I just spotted on another thread. I'm really in two minds in sand. I love the look of dark sand but
Argos sand is €5.50 for 15kg. My husband says it's the equivalent of getting nice take away so bit to stress on price point. But all I think is €30 extra here is €30 less on plants and fish
Aaawww, thank you so much, that means a lot!
I'm the same way, I want chill, peaceful fish, the idea of nippy, super territorial fish or balancing aggression by overstocking in something like a cichlid tank terrifies me, lol. Small peaceful fish or bright beautiful schooling fish and bottom dwellers appeal to me the most. I avoid barbs for that reason.
@mbsqw1d got some odessa barbs recently and while they're stunning fish and really beautiful in his planted tank, they also decimated his shrimp colony
so that ruled them out for me, I love having shrimp.
I know you're kidding about the spreadsheet, but it's actually not a bad idea! I suggested it to someone who was trying to narrow down fish options, and having columns for pH, GH, temp etc would really make it easier to see which ones can fall into the same range! I haven't used Excel for years so I haven't, but it could be really useful when you have a long list of fish you're thinking of.
The sand I have with the cories is this one, which seangee uses and recommended, I'm happy with it!
https://www.pro-shrimp.co.uk/sand/1924-unipac-limpopo-black-sand-25kg-5027174581291.html
They're out of stock right now but you can get the same stuff elsewhere, just a little more expensive. It says that it's black, but it's really more of a dark grey with some lighter flecks in it, which is good, since a true black substrate would be too dark for some fish. A 20kg bag was enough to do my 15 and the 12 gallon, with a good amount leftover;
Personally I think it's worth spending a bit more on substrate, since it's the bedrock of your tank, and changing it later if you end up hating it is a hassle. I spent more on sand and hardscape than I'd like, and it meant I could only get a few plants at first (make sure you get shrimp safe plants if you're thinking of shrimp, btw!) but I know I can always add more plants down the line far more easily than I can replace substrate.
Having said that, lighter coloured sand can look brilliant too, so I don't think the argos play sand is a bad choice either! I was going to buy some for my oto tank, just to have a different coloured substrate (and for cheap!) but have been reading about some of the species I like preferring darker substrate and having better colour on dark substrate, like ember tetra... so still pondering!
though when I first got Plecos I was the same & now they're my favourite 
