@Lee2Gould, did you ever find a solution? I was searching for something else and found this conversation. Your problem sounds an awful lot like the issues I had when I set up my tank. I have fairly neutral pH, soft water and most importantly very low nitrates.
I also have a planted tank. You said you had plants, but they weren't thriving. How many plants do you have and what type of plants.
I eventually discovered that the issues included low calcium (not hardness, which measures carbonate part of the calcium carbonate), which both fish and plants need. Fast growing stem plants and faster swimming fish need more calcium than slow growing /swimming plants and fish.
The ratio of phosphate to nitrates is also really important. The phosphate comes from the fish food, so you need to make sure that you have enough nitrates in your tank to enable the plants to use up the phosphate.
When considering terrestrial plants, fertilisers always talk about NPK, which is nitrogen, phosphate and potassium. Aquatic plants are the same, and it is the balance between these three macro nutrients that optimises growth and water conditions.
I finally got my tank into good condition by adding calcium nitrate and potassium nitrate salts at water change (as well as dosing liquid micro nutrient fertilisers). Once I'd sorted the plants, the fish started to thrive and as I increased the number of fish in my tank, I was able to reduce the additional nitrates.
Something else to note is that a lot of easy to care for starter plants have high demand for nitrates - this is good for most people who have to keep nitrates down with water changes. Less good for those of us that have water with low nitrates. My Amazon sword died completely when my tank got neglected and I stopped adding nitrates.
Hope it isn't too late for your tank.
Helen