personally for such a low stock in your tank in regards to plants then there is no need to have ferts or even dose co2 if u stick with low light and low demanding plants like u have all will be good plant wise how are you doing on the food front? they started eating any food u put in yet??
lol but luckily my filter is big enough to take the load, one of the shrimp tho has a red thing inside its head similar to your yellow spot on your blue shrimp i wonder too what this is? this shrimp is much larger then my current ones and larger than any i bought il try and get a pic tomo going to do a big clean and my plants need a trim and rescaping so il see and mix around things tomo, my 2nd tank for the shrimp tho is going well half way through the cycle ammonia 0 now for 3 days in a row but my nitrites staying high won't go down was over 5ppm other day till i did that dual 90% wc it was 1ppm yesterday and slowly increased to 2ppm today will do another wc tommo tho but i did buy some bottle bacteria to see if that will help, not the same stuff i usually get that DOES work on nitrite but il see if this works