Proper O2 Levels for reef fish

[sledge760]

Can someone tell me acceptable/minimum O2 levels for reef fish? I bought a Salifert Oxygen test kit and am coming up with barely 6 mg/l. Is this too low, acceptable, or obviously not to high? All my fish, only in the evening (for some reason) are all rabidly breathing at the bottom of the tank. They do not swim around and seem stressed.

 

[pencil3]

I don't think DO is your issue, I have a dissolved oxygen probe that reads 5.8 ppm on my tank.

Can someone tell me acceptable/minimum O2 levels for reef fish? I bought a Salifert Oxygen test kit and am coming up with barely 6 mg/l. Is this too low, acceptable, or obviously not to high? All my fish, only in the evening (for some reason) are all rabidly breathing at the bottom of the tank. They do not swim around and seem stressed.

 

[jd474]

mg/L measurements are highly dependent on temperature and salinity. Do you have a % saturation? Regardless, that probably isn't your issue; that number is right in the ballpark.

 

[sledge760]

I do not have a % saturation. If 6 mg/l is ok then I will have to look for other issues. All my other levels are good.

 

[Luiz Rocha]

How many fish and what size tank? Also, how many inverts?

 

[Recty]

I had a similar problem with a tank of mine, I noticed it three days in a row and realized I needed to do something to fix it.

What fixed mine was doing a decent sized water change, about 25%, and I started running carbon in one of my filters. The next evening, the problem didnt rear it's ugly head again and never happened after that.

I cant say exactly what caused it, but I do know what seemed to fix it. Anytime your fish seem weird for no apparent reason, it is a good idea to do a good sized water change and see if they start acting better.

 

[sledge760]

155 gallon softie tank (light load of coral) and a few snails. 25% water changes weekly. All parameters in the normal range. I have been dosing vodka for 6 moths with no issues. I have noticed this happening for around 2 weeks now.

NO3: 0
PO3: 0.5
CA: 1475
Mag: 1400


Fish list:
Green Spot Puffer
Yellow Tail Damsel
Three Stripe Damsel
Hippo Tang
Kole Tang
Blonde Naso Tang
Pink Tail Trigger
Orange Shoulder Tang

 

[Luiz Rocha]

And it keeps happening even after the water weekly changes? That's really odd, O2 levels should come back to normal after that.

 

[sledge760]

yes even after water changes, in fact every night in the evening around 8:00pm. Really strange.

 

[auem]

your calcium is 475,not 1475 i hope...

 

[Recty]

What's your pH? Maybe it's dropping during the day? Might be worth checking it at night.

 

[sledge760]

yes 475 on the ca. ph runs 8.0-8.2. I will have to check ph when the gasping starts again tonight.

 

[Recty]

What did the pH test reveal?

 

[sledge760]

Still happening every night and driving me nuts. PH is around 8.0 when the gasping is going on. Did a 30 gallon water change this afternoon also.