Hello Iroc,
First, here is a link to Tim's Fish Compatibility Site.
http
/www.timstropicals.com/Compatibility/NameResults.asp
I would suggest you do more research on the fish you have in respect to them having an appetite for shrimps.
Sorry ,but I am not familiar with your fish.
BumbleBee shrimps tend to eat plants if they don't have enough food. They only live for about a year.
I would suggest the Amano shrimp. I've had mine for 3 years now.
Java moss does well when trimmed regularly. They abosorb nutrients from the water directly as they have no roots.
The other plants you have take most of their nutrients through their roots. Try increasing your liquid fert a little (2 to 5 ml extra).
Your fish load seems fine. Try adding more plants (fast growing) to keep your water stable and to remove toxic elements from the water as well as other nutrients that other organisms like fungus and algae would need to grow.
You say you've had the tank for 4 months but the tank is 4 yers old.
Does this mean you had set up the tank from scratch and it's been up and running for 4 months? A tank your size will take longer to cycle and 4 months is not enough. Filters are designed to remove large particles from the water, nothing else.
Your bacteria colony grows in the substrate, on the plants, bogwood and slate as you have, so avoid disturbing the substrate too much when vaccuming. Just do the surface to remove left over food and what have you. Remove the activated carbon from your filter. It will absorb ferts. Use floss pad or sponge only and clean the filter every two weeks. I have never tried using sand as a substrate so I have no comments on that. The slate is something I would be concerned about as it will leech. There are so many types of slate out there and each type will have an effect on your water chemistry (ie: iron, copper). Do make sure it is safe for your fish and shrimp that you may add in the future.
As for your tank , over all, it looks Great!
The one thing I would do though is let the Vals multiply and plant them in the back
and I would plant glosso in the foreground. This will however require you to add CO2.
Regardless of what you do, the plants will benefit from added CO2, even just a DIY type.
The white stuff will come back if you over feed. Try feeding once a day for a few days and see how it goes.
The fish will be fine. All the best.