Check the nitrate level of your source water too.
Plants grow well in my tank and keep nitrate very low, often zero, despite my tap water being at 35ppm. Although nitrate is an essential nutrient, I have found that once it gets to higher levels, plant growth is stunted. This in turn leaves other nutrient levels unused so those build up as well, further promoting algae growth.
If I start a new tank I struggle to get plants to establish and it took me a while to work out that this appeared to be the issue.
Given the high level in my source water my solution is to use a nitrate reducing resin to lower the level which I find seems to kick start the plants. I've used Nitragon which removes most Nitrate within a couple of days. I wouldn't recommend long term use as it's an ion exchange resin, however, it's great where you need a temporary fix - once the plants get growing they deal with the nitrate which the tank produces, and which I am adding every time I do a water change.
Check also that your well water isn't high in phosphate. Weirdly despite having high nitrates in my tap water, it actually has zero phosphates and whilst it is well known that high phosphates can cause algae, it's another essential macronutrient, so low levels can do too! Algae was starting to become an issue in my tank about a year ago and plants were starting to suffer. I initially suspected high phosphates but when I tested for these and found that they were zero both in the tank and in the tap, I suspected that the vigorously growing plants were actually suffering from a lack of it. I started dosing to keep levels around 1 - 2ppm and the problem cleared up. I test weekly and it's quite volatile - I might dose to bring it up to about 2ppm one week and the next week it's hardly changed so nothing more is added, but on other occasions it will drop from 2 to zero in a week and need a further full dose.
Just trying to illustrate how it can be hard to get the balance right and keep it right!