Sinsemillla, algae uses up oxygen.

I was able to create low temps in the 40-50's just by leaving a hydro container outside. Even though I had a pump going all day, it still wasn't enough and I quit doing hydro outside till the weather gets nicer. The plants came in every night where the water stayed in the 70's. Once I started leaving the plants inside, they started growing. I shocked them everyday for a month and still got one female and 3 males in hydro. I'm waiting to see if the hydro female will turn hermie.

Thank you for posting all those websites on you messages. Very helpful.