Could you provide a photo of your floating plants? Floatingplanthave first access to light and have unlimited access to CO2 in the air. In my experience with floating plants is that they can grow as fast as any stem plant. So
if the floating plants are not doing well it is probably because they are not getting enough nutrients from the water Such as nitrogen, potassium, calcium, magnesium, sulfur, iron, manganese and several others There are a total of 14 nutrients that are essential for growth. If just one is missing plants will not grow. and eventually they may die. With minimal plant growth plants will not be able to alter your PH and KH. Also with your KH as high it is simply impossible for plants to correct the problem.
Calculate how much distilled water you will need for a year and the calculate how much that will cost. You will likely spend more money to buy distilled water than a RO unit would cost aless even if you facto in the replacement filter costs.
this RO system cost $60 and can be connected to a facet in only minutes when it is needed. And it can produce 50 gallons a day. However note that I don't own this system.
Also with no fishing your tank the is no fish waist to provide any nutrients.your plants that are growing are probably theones that are speciallist at surviving in nutrient poor water. Also with your KH and PH as high as they are it will be hard to maintain adequate iron and magnanese levels in your water.
- Well in my tank plant growth pushes the PH up. Not down. I have to dim the lights to keep it close to 7. If I run at brighter light levels my ph will exceed 8.5. And it is apparently related to plant growth.
- Amino acids are are primarily found in the DNA of plants. As long as the plant is healthy the amino acids will not be floating free in the water.
- Aminoacids are not soluble in fresh water. Apparently they are only soluble in the salty solution that fills the cells of plant.
- Plants and bacterial quickly consum it because it is a great source of nitrogen. So if you have a lot of fast growing plants they will remove any amino acids in the water.