The 2.5l bag of Growth Substrate is a good amount for that tank footprint - you want a clean line at the edges (assuming a rimless tank) so the GS should be kept 1-2cm back from the glass sides
Tropica Soil - I strongly recommend
the Powder as it's much easier to plant in than the larger particle version
seen here (note demo plants are pushed into the dry substrate but this is unusual).
I used less than 2 bags of Tropica Powder for my 60cm x 45cm, substrate depth ranges from ~ 6cm - ~13cm
Note that even once tank is established the larger particle soil is considerably more "slippery" for replanting than Powder.
You can use just the Soil without GS but I always use both (tap water is very soft)
I wouldn't add any Osmocote etc initially - there is going to be so much available nutrients just from the Soil & GS
Initial planting with tank essentially dry & substrate just damp, is the easiest time to plant as the substrate is less "slippery", but take care to (gently) push plants deep enough to prevent them floating off once tank is filled ... this happens partly from water current & partly from trapped air in the substrate pushing free - & taking some plants with it
If planting HC, you might also use toothpicks to help hold the plants in place (unless you go with almost individual stems)
A watering can with a
fine spray head works great at gently adding water to substrate, then spray/mist as you plant to keep leaves damp.
If you've the patience you might carefully fill the tank - a good idea to check hardscape layout through water vs air re perception & colors (I've some Yamaya stone with GLITTER
😱 ), also it's preferable to have wood float off WITHOUT plants ... I'm now a great believer in Rock ON Wood at the start up! - then drain tank back to substrate level before planting.
To facilitate removing as much water as possible, I leave an area at one corner that is bare glass (I use some bendy plastic for this)
just noticed your post count - I suspect you don't need my "tips" ... but I'll leave them anyway
🙂
