Your algae issues are a C02/light issue, alot of folks think that it may be N03/P04, Mg or Calcium, but it is not, I have been using the sticky levels in all my highlight tanks to the Tee for a long time, any algae issues I have seen, have all been related to light and C02, it is learning to manage those two elements properly that will correct the problem.
It is not KN03, P04, it is not Mg, or Calcium, but light/C02
It does not matter if it is a Sand sub, or Flourite sand, Eco Complete, Flora Base or ADA Aqua Soil, I have and use them all, it is managing the light/C02.
I also have medium soft water, and use RO water, it is still the same, light and C02.. as long as you give the plants KN03, KH2P04 and Trace, the rest is light and C02, same issue time and again.
Learning the plants is key.
Proper diffusion is a must in a highlight tank, managing the lights are a very important factor, to much light to fast causes problems, reduce the light intensity for the next couple of days while maintaining a strict dosing regime and good C02, you should see a noticable difference rather fast.
Don't complicate the issue, Keep it simple. Look to the light/C02, with good dosing..
Light is the driving force of a tank.