Oxygen issue this morning, looking for causes

[G&B Reefing]

6:30am: 7.8 (with airstone)

 

[Jay Hemdal Verified Community Expert]

not sleeping so i am reporting some ph measurements:

8pm (almost lights out): 8.2
10pm: 8.0
12am: 7.8

I chickened out and placed the airstone back in.

Notes. Measurements using red sea ph test kit. Apparently this is the only kit they have where the colors actually match the card…

There is a safer way to test this: take a half gallon of water out before lights on in the morning, measure the pH, then aerate it for 8 hours and retest.

The drop you saw in four hours does seem to indicate there is a gas exchange issue….

 

[Jay Hemdal Verified Community Expert]

6:30am: 7.8 (with airstone)

To me, that indicates the pH would have gone even lower without aeration.

That said, accurate pH measurements are always a challenge.

 

[G&B Reefing]

There is a safer way to test this: take a half gallon of water out before lights on in the morning, measure the pH, then aerate it for 8 hours and retest.

The drop you saw in four hours does seem to indicate there is a gas exchange issue….

I did a water change this morning. Got this test setup on half a bucket (~2.5gal). Will report numbers this afternoon.

 

[G&B Reefing]

Also, for what its worth here is a pic of the tank. I am fighting some algae but it has not fully taken over. Also you can see the surface agitation in the pic.

 

[Jay Hemdal Verified Community Expert]

I did a water change this morning. Got this test setup on half a bucket (~2.5gal). Will report numbers this afternoon.

The water sample needs to be before lights on and before any water change....

 

[G&B Reefing]

The water sample needs to be before lights on and before any water change....

Water was removed prior to lights on(beat lights on by 15 minutes!!). Test water is not diluted with new water, came out from the tank and set aside prior to putting “new” water in to replace.

 

[G&B Reefing]

Have measured the test water ph a few times already.

9am: 7.8
12pm: 8.0

 

[Jay Hemdal Verified Community Expert]

Have measured the test water ph a few times already.

9am: 7.8
12pm: 8.0

That's not a significant pH rise....

 

[G&B Reefing]

That's not a significant pH rise....

The test water is still measuring 8.0 as of right now.

The tank went from 7.8 this morning to 8.2 as of right now.

 

[larrysaltisfun]

Maybe farfetched, but could you have had a power outage for several hours that reversed by morning just around the time you woke up ? maybe the fish recovered coinciding with the time airstone placed

 

[Jay Hemdal Verified Community Expert]

The test water is still measuring 8.0 as of right now.

The tank went from 7.8 this morning to 8.2 as of right now.

A rise of 0.4 pH units shows a small amount of CO 2, but not a dangerous amount IMO.

 

[mcarroll]

This thread may be a bit stale, but R2R sugested it I guess....

6:30am: 7.8 (with airstone)

If you were getting 7.8 with an airstone running then IMO that indicates high CO2 levels in the room where the tank is. (Specifically, where the air pump is.) CO2 could also be high in the whole house.

Some resources:
https://www.reef2reef.com/posts/8063654/https://www.reef2reef.com/posts/13990580/