Low PH (didn't see this one coming)

[SkinnyPete]

Well, I just tested PH (3 times, just to make sure) and I'm at 7.8. I just did a 20% water change this morning and I tested the new water getting 8.2. The only thing new I added was chaeto about a week ago. I've never had PH problems in the past. Always reading 8.2.

How dangerous is 7.8 to inverts? Just got a giant clean-up crew after getting my NO3 to an acceptable level, now this. Do I just do several water changes in the next few days to get it down?

- Skins

Also, just dosed Iron if tha matters.

EDIT: Just tested with a better PH kit (SeaChem) - and I'm getting about 7.9. Tried to test Alkalinity but I"m not digging this SeaChem Alk test kit. The color is not changing so either my alkalnity is really high, the test kit stinks, or I'm color blind.

 

[cmor1701d]

What time of day are you testing and is it the same time of day as your prior testing?

pH will be lowest just before the lights come on and highest just before they go off.
You don't have a glass top do you? That can cause low pH due to poor gas exchange at the surface.
What salt mix are you using? What SG are you mixing to?

As I remember the SeaChem tet kit it had a plastic tray with wells for the tank water and you put a drop of the pH test in. The color chart was graduated color strip. Is that correct?

I switched to a pH monitor because I didn't feel comfortable with any of the test kits I used.

 

[SkinnyPete]

Yes, on the SeaChem. It was a little over 7.9. Red Sea test kit says 7.8. I tested at the same time I usually do. Mid-day. I run my main tank (110g) open top, half of my sump (50g) is covered by glass. I'm assuming I have good gas exchage - my return pump pushes about 700gph and ripples the surface. Plus the drain in my sump is just under the surface and really blows the top of the water around.

I guess 7.9 isn't exactly "dangerous", but I should work on bringing it up - correct?

 

[MT79]

Have you opened any windows in your house lately? CO2 tends to accumulate in houses during the winter months because of the use of heaters and a lack of fresh air.

I guess 7.9 isn't exactly "dangerous", but I should work on bringing it up - correct?

It's not horrible but I would aim for atleast 8.1 at mid day. Remember not to make water chemistry changes to fast. Best to raise the PH, when all else fails, by doing PWC's over the course of a couple/few days IMO. If you plan on using any buffers be sure to get a good, definitive reading for Alk first. I prefer PWC's over additives to correct unexpected chemistry shifts. HTH