Well...pretty much what the title says. I need a way to test for dissolved oxygen in my tanks because I don't like all this guessing business. I need accurate readings for everything so I know exactly what's going on.
If I need a different meter, can someone please point me in the direction of where I can get one?
Thanks for looking

Just wondering, but why do you need to know the oxygen levels?

So I know that my fish are happy and comfortable. I see them up at the surface sometimes and it makes me wonder if the oxygen level is high enough...