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New tank..Green water

14K views 15 replies 10 participants last post by  Karen  
Are you using RO water? If it comes out of the tap like that you are very lucky! But, your low KH is the reason you are having trouble with the pH. With a KH of "0", I would not add CO2. 3-5 dKH is good for a planted tank, since almost all plants prefer soft water over hard, and that pH can hold a somewhat stable pH with CO2.

The reason your plants are probably thriving right now is b/c the available form of nitrogen to them is ammonia, which plants love. In order for plants to use nitrate, they need to spend energy to break it down to a useable form. However, ammonia is toxic to fish, and this breaking down of NO3 is pretty easy if you have provided proper nutrients, CO2, etc... for the plants.

When I started my tank, I had your exact same lighting, and I got algae, but not green water. Recently I got green water from fertilzing and not having enought plants, and the blackout for 4-6 days works. It may seem scary, but it works temporarily. Like Buck said, this green water is from excess nutrients in the water collumn, so if you did sub-ferts, make sure they are deep enough. If the source of nutrients is not eliminated, then the green water willl just come back.

I know this may seem frustrating, I have had nights where I ALMOST regret getting the planted tank started (I'm in 9th grade and have lots of other things going on), but now that mine is coming together, I have no regrets what so ever. After I found this forum is when it started turning around. Good luck with the tank!

-Tim :fish: