constant low pH

archgetty

New Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 9, 2020
Messages
10
Reaction score
3
Review score
+0 /0 /-0
Location
Santa Monica CA
I have read the posts about low pH but none of them describe my situation.

My daytime pH is around 8.0. Nighttime 7.7. I would like 8.3.

130 gal tank

- Alk: 9.5
- CA: 450
- Mag: 1350
- Kalkwasser ATO
- supplemental dose All-For-Reef
- Tank is in a room next to big doors which are always open to outside air. (I live in Los Angeles)
- 20% water change weekly

- 2 quality pH probes, calibrated up to date

I'm tempted to add a buffer but fear that my Alk might go through the roof.

Any suggestions welcome!
 
AquaSD

CoralB

2500 Club Member
Review score
+0 /0 /-0
View Badges
Joined
Mar 20, 2021
Messages
3,170
Reaction score
11,708
Review score
+0 /0 /-0
Location
Orlando, Florida
If you have a skimmer you could try to add a co2 scrubber on the intake of that skimmer . I know you said the two doors are always open and with your alk in good standing that’s the only thing I could suggest .
 
Nutramar Foods
OP
A

archgetty

New Member
Review score
+0 /0 /-0
View Badges
Joined
Jul 9, 2020
Messages
10
Reaction score
3
Review score
+0 /0 /-0
Location
Santa Monica CA
Are you running a refugium on opposite light schedule?

Can you take a nighttime sample whe ph is low and aerate it to see if the ph comes back up?

I wouldn't add anything just to chase a ph number.
Thanks! Yes, refugium on opposite light schedule. Also algae scrubber ditto. Tried aeration already.
 

Randy Holmes-Farley

Reef Chemist
Review score
+0 /0 /-0
View Badges
Joined
Sep 5, 2014
Messages
54,616
Reaction score
47,424
Review score
+0 /0 /-0
Location
Arlington, Massachusetts, United States
Adding a "buffer" is a poor idea pushed by marketers that either do not understand chemistry, or don't care about being honest.

You are using a low pH alk method. Other alk methods can give a substantial pH boost.

I suspect pH measurement error if the doors are always open, but try this aeration test:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.
 

Randy Holmes-Farley

Reef Chemist
Review score
+0 /0 /-0
View Badges
Joined
Sep 5, 2014
Messages
54,616
Reaction score
47,424
Review score
+0 /0 /-0
Location
Arlington, Massachusetts, United States
Thanks! Yes, refugium on opposite light schedule. Also algae scrubber ditto. Tried aeration already.

If alk is above 6 dKH and sufficient aeration with outside air does not raise pH above 7.9, then you have a pH measurement issue, not a low pH issue.
 
Corals.com

dblhelix

New Member
Review score
+0 /0 /-0
View Badges
Joined
Jun 20, 2021
Messages
11
Reaction score
3
Review score
+0 /0 /-0
Location
Madison
Adding a "buffer" is a poor idea pushed by marketers that either do not understand chemistry, or don't care about being honest.

You are using a low pH alk method. Other alk methods can give a substantial pH boost.

I suspect pH measurement error if the doors are always open, but try this aeration test:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.
Randy,
My reef tank suffers from 7.59 at night to 8.0 pH in the day range. A few months back the pH was about 8.0-8.4. I use All for Reef and not 2 part or Kalk. All is about 8.6 and calcium is about 460. I have a great refugium that I have to harvest at least once a month running the light on it only at night.

The only thing I changed was I added 22 more pounds of sand because a watchman gobi hoarded about 1/4 of the existing sand in one corner to build his home resulting in a big bare spot in the middle of the tank where the powerheads create the most current. I used to have only about 1 inch of sand and now that is about 2". Its a 73 gallon tank with 18 gallon sump. Do you think this sand addition has maybe increased the carbonic acid and lowered my pH. Have you ever heard of this happening? Thank you.
 

Does it matter to you whether your fish are captive-bred or wild caught?

  • I only buy captive bred fish.

    Votes: 32 12.7%
  • It matters, but I will buy either captive-bred or wild-caught.

    Votes: 194 77.0%
  • I think wild-caught fish are the better option.

    Votes: 3 1.2%
  • I don’t care where the fish were bred.

    Votes: 23 9.1%
Bulk Reef Supply
Top