Used fish tank water okay for watering orchid?

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Hi, I have a few Amazonian biotope style planted aquariums that I change water on the weekly basis(about 30 gallon removed weekly). Here are some of the parameters of the used fish tank water.

-Temp 82F
-PH between 6~7...slightly acidic
-GH low, the general hardness is low right out of our
NYC tap.
-Chlorine/chloramine/heavy metal removed by consumer aquarium water conditioner, no chemical added.
-used tank water contains a good amount of phosphate/nitrogenious waste(Nitrate) from the fish waste which are good fertilizer for aquatic plants, but not sure about Orchid.

Would anybody recommend I use this water for my Orchid?

thanks in advance and here is a pic of my tank