Your plants need 12 hours a day at the very most, I'd recommend 5.5 hours on, 2 hours off and 5.5 hours on. It'll be more than enough for the plants and will help keep the algae down.
Do you know the Nitrate level of your tapwater?
How often do you change the water?
80 is very high and getting to the level that could harm your fish.
Assuming that your tap water is a lot less that 80, increasing the frequency of your water changes will help to stop this happening agin.