How Do I Know If The Oxygen Level Is Right?

Hello experienced fishkeepers, besides really expensive test meters, there isn't really a way to measure the level in a tank, is there? And is there ever such a thing as too much dissolved oxygen? I have a 20G with an aqueon HOB filter. I always thought the flow seemed strong from the output and there's always a constant stream of bubbles from it which of course pop on the surface causing even more agitation. But some bubbles were sticking to the surface biofilm so I added an air stone to break it up. The airstone adds extra current and extra stream of bubbles on the surface that I wonder if it's too much for the fish I want to keep (guppies/honey gourami). Also, it's literally raining inside the hood of my tank from all the bubbles popping on the surface, hitting the lid and dripping into the tank. So, is having the extra current/air more of a benefit to the tank or is there any reason to believe I would ever have too much? By the way, this is a low light/low tech tank with mostly slow growing plants so I don't think they would affect the level too much.
thanks!

 

I don't think you will have too much oxygen but you could certainly have too much flow. Honey gouramis prefer quite still water, especially near the surface where they breathe air. Fancy guppies with long fins can struggle with high current.

 

I don't think you will have too much oxygen but you could certainly have too much flow. Honey gouramis prefer quite still water, especially near the surface where they breathe air. Fancy guppies with long fins can struggle with high current.

Agree with this. Your main main concern in less water flow. Try to find a airstone that makes smaller bubbles. Will create less water flow. The honey gourami is fine because it can breathe from the surface with its labyrinth system thingy

 

Yes, the water flow is a concern. I'm trying to balance having enough filtration and enough oxygen without creating too many strong currents. As long as there's not a chance of somehow over-aerating the water I will probably keep a small airstone running and try to soften the output on the HOB filter somehow.

 

Hi

As long as there's not a chance of somehow over-aerating the water

There is no such thing as over-aerating the water.

 

I feel no one has explained why you won't over oxygenate a tank. Short of diffusing oxygen into the water like some do co2 the gas exchange is only from the air in the room. So once equilibrium is obtained that's the amount of oxygen in your tank water. Along with all the other stuff that makes up air.

 

Yes, the water flow is a concern. I'm trying to balance having enough filtration and enough oxygen without creating too many strong currents. As long as there's not a chance of somehow over-aerating the water I will probably keep a small airstone running and try to soften the output on the HOB filter somehow.

Get some kind of sponge to put on the HOB filter's output. Just get a mechanical filter pad. Can find it anywhere for very cheap.