Bubble disks

[michael]

If I have dissolved oxygen of 9 ppm do I need to have a bubble disk running in my goldfish tank.

[exv152]

If I have dissolved oxygen of 9 ppm do I need to have a bubble disk running in my goldfish tank.

Optimal concentration levels are between 5-7ppm.

[bizfromqc]

If I have dissolved oxygen of 9 ppm do I need to have a bubble disk running in my goldfish tank.

May I ask how you got the 9ppm?

If you take a look at the table here:
http://www.aquatext.com/tables/oxygen.htm

If we assume that you keep your goldfish between 20-22C (I believe the recommended temp range) and you have 0 salinity (freshwater). 100% rate of dissolution would give you 8.73 and 9.08. I've read that the average rate of dissolution in a fish tank is around 70%, that would put you between 6.1 and 6.3.

So what's your secret, colder water or higher rate of dissolution?

[michael]

I have fancy goldfish. Ya I do not have salt in my tank. My tank temp is about 73 to 74.

My bettas tank oxygen is about 7 ppm and his water is about 79°F

I just use a test kit when testing the dissolved oxygen.

I notice that the tables all have something to do with salt in the water.

All I have is two pumps and one bubble disk in each tank.

I was wondering if I could do away with the bubble disk?

[exv152]

...I was wondering if I could do away with the bubble disk?

The simple answer is, yes. But I would just put it away, and not do away with it. It always comes in handy to have.