Critique my aquascape Constructive critique on my first tank

[FrozenShivers]

Just got home from a long day of work, sadly one of my shrimps has passed. Really gutted as just feel like I've failed the poor fella. Done a quick test and ammonia is 0ppm, Nitrite is 0ppm and nitrate is around 10-20ppm with PH being the usual 6.8. Not sure what I've done wrong, attached pictures in case anyone spots anything and can advise me. This is my first aquarium so I'm an amateur and all I can think of is that I've overdosed Bacter AE or something to do with the snails I introduced to their tank last week? Currently waiting on some water getting up to temp so I can do a water change.



Edit - Temperature seems fine also, 23 degrees.

 

[Hufsa]

sadly one of my shrimps has passed

With the white ring around the body like that I would say its a failed molt

 

[FrozenShivers]

With the white ring around the body like that I would say its a failed molt

Thank you!

 

[FrozenShivers]

Touch wood everything has been ok since the last shrimp death. I added 6 Least Killiefish to the tank, I now figured I'd give them all some more space so I have a 60x30x30 54l aquarium arriving tomorrow which I will transfer everything from here into and sell the old tank