I like to avoid the use of heaters if possible because they can fail and electrocute your turtle and potentially burn your house down.
Ask yourself how cold do you let your house get ever? Is it above 60f? You don't need one then.
I recommend this timer. I have 3 of them: GE 24-Hour Heavy Duty Indoor Plug-in Mechanical Timer, 2 Grounded Outlets, 30 Minute Intervals, Daily On/Off Cycle, for Lamps, Seasonal, Christmas Tree Lights and Holiday Decorations, 15075 https://www.amazon.com/dp/B00366JSNU/ref=cm_sw_r_cp_apa_i_eFQpFb4MJG3TJ
Don't feed your turtle daily or worse twice daily.
Change your UVB/UVA bulbs every 6 months if they are CFL like this one: Zoo Med ReptiSun 10.0 Mini Compact Fluorescent Lamp https://www.amazon.com/dp/B00A8RHTYU/ref=cm_sw_r_cp_apa_i_VGQpFb6P1DE4G
YBS need extra UVA/UVB so go with the bulb I linked or a similarly powered one.
You also need cuttlebones. Exo Terra Sepia Bones for Turtles https://www.amazon.com/dp/B002YPZDBK/ref=cm_sw_r_cp_apa_i_eIQpFb2ZFDZR0
Any cuttlebones will do though.
Here's my water treatment: API QUICK START Freshwater and... https://www.amazon.com/dp/B006YG12F6?ref=ppx_pop_mob_ap_share
API TURTLE SLUDGE DESTROYER... https://www.amazon.com/dp/B00ESBHN1Q?ref=ppx_pop_mob_ap_share
API TAP WATER CONDITIONER... https://www.amazon.com/dp/B004LO9KSY?ref=ppx_pop_mob_ap_share (FYI you almost certainly have chloramine not chlorine in your water.)
API AMMO-LOCK Freshwater and... https://www.amazon.com/dp/B000255N0A?ref=ppx_pop_mob_ap_share
Get this to test your water: API Freshwater Master Test Kit https://www.amazon.com/dp/B000255NCI?ref=ppx_pop_mob_ap_share Ammonia, nitrates, and nitrites are your enemy.
Don't buy a dock. Make one from egg crate diffuser materials and zip ties: https://youtu.be/KDb6cv5I9Tg
Your turtle needs to get fully dry on top and bottom or they will get shell rot. I had a zoomed dock that cost 50$ and I replaced it after a scare with shell rot.
More substrate. You can add it slowly & gently, about an inch at a time while they're down.
Heat source - you canpurchase a heating pad for cheap and stick it to the side/back of the tank (not underneath)
Deeper pools - salt & fresh you want them deep enough for your largest crab to fully submerge in but easy enough for the smallest to climb out of. Food storage containers are cheap pools and craft mesh works well for ladders.
Reptivines are great decor and provide climbing and hiding opportunities.
Additional hides - having multiple hides help prevent territory fights. I have a couple of terracotta plant pots turned on their sides and stuffed with moss to help with humidity
Additional levels - you can create more space by adding shower shelves or similar - mine are moss pits and include foraging opportunities
Foraging - I have urchin shells stuffed with foraging mix stashed around the tank - moss shelves.
Shells - you can never have too many. They should be size appropriate and larger... turbo shells are pretty popular with most land hermies. Shell opening measurement is what you want to pay attention to. You look like you've got a decent collection of appropriate shells(depending on your crabs size)
Honestly though you look like you're off to a great start with a solid foundational set up. Beyond deeper substrate and pools everything else is gravy.