Low pH /alkalinity incorrectly freshly mixed saltwater

[Mykawl]

Low as in pH 6.0 or so, at first I thought it was just c02 so I got the pump going right at top of water etc won’t bring it up higher enough but as randy has explained the only other reason is alkalinity.

Alkalinity is 6.0...

Only guess is because originally I was using the wrong refractometer and salinity was 1.040 or higher anyways I eventually got the right device and added ro/di until 1.026

I do not have an alkalinity supplement atm.

If I add an air stone to adjust pH (if it even brings it up high enough) and was to use this water I’m wondering if the pH would just simply drop back down in display tank because there is missing alkalinity. Also I understand I shouldn’t be adding this water to my tank anyways if dkh doesn’t match.

Was the alkalinity somehow “used up” because the salinity was so high and when I brought salinity back down alkalinity was still slightly depleted?

Is it correct to say I have a huge bucket of useless fresh water until I can adjust alkalinity and consequently pH?

 

[Mykawl]

What is curious is thank the dkh of my tank is 7 or 8. Was wanting to do a big water change because nitrates are high 20-40 but this would cause more harm no? All corals seem to be doing fine

 

[Mykawl]

Added air stone and pH definitely rising 7.8-8.0 hard to tell with API but going to hold off on water change until I can adjust alkalinity.

 

[Mykawl]

Double checked and tank is closer to 7.0 than 8.0, will I be able to just use Tropic Marin AllForReef since this is what I was planning to use when I got to dosing.

Wait a second I think I’m confusing myself, can I just add baking soda?

Edit: baking soda seemed to do the trick, used the calculator on BRS website. I originally thought baking soda raised pH but it effects alkalinity which in turn effects pH... anyways don’t want to confuse myself or anyone any further gonna do that water change now : P

 

[redfishbluefish]

No way could your pH be 6. I do not trust the kit you are using to measure pH, and actually wouldn't be overly concerned with pH if your alk, calc and mag are in line. Get those numbers straight and you'll be good to go. Don't chase pH.

 

[Mykawl]

Any suggestions on ph meters? Also your right I probably got that mixed up with alkalinity numbers the colors are hard to read. Alkalinity was the one at 6.0 or so

 

[rkpetersen]

Baking soda (sodium bicarbonate) has relatively mild effect on pH but will increase alk.
Washing soda (sodium carbonate) has a larger effect on both pH and alk.
Water changes won't hurt if the alk level of the new water is similar to that of your tank.
If the alk in the new water is much higher than in your tank (the case with some jacked up salts), a large water change could shock some corals. In this case, multiple smaller water changes would be safer.
All pH meters need to be calibrated from time to time. Hanna makes some reasonably priced handheld ones.

 

[Randy Holmes-Farley Verified Community Expert]

Low as in pH 6.0 or so, at first I thought it was just c02 so I got the pump going right at top of water etc won’t bring it up higher enough but as randy has explained the only other reason is alkalinity.

Alkalinity is 6.0...

Only guess is because originally I was using the wrong refractometer and salinity was 1.040 or higher anyways I eventually got the right device and added ro/di until 1.026

I do not have an alkalinity supplement atm.

If I add an air stone to adjust pH (if it even brings it up high enough) and was to use this water I’m wondering if the pH would just simply drop back down in display tank because there is missing alkalinity. Also I understand I shouldn’t be adding this water to my tank anyways if dkh doesn’t match.

Was the alkalinity somehow “used up” because the salinity was so high and when I brought salinity back down alkalinity was still slightly depleted?

Is it correct to say I have a huge bucket of useless fresh water until I can adjust alkalinity and consequently pH?

None of those things will cause that low of pH. I expect test error.

 

[Mykawl]

Sounds good I keep getting different results user error for sure just gonna upgrade everything and throw away old water.

Just want to cover all bases here I often use this for top off water any concerns?

 

[Randy Holmes-Farley Verified Community Expert]

Why use that? RO/DI might be better since you cannot tell how much of those ingredients they add.

 

[Mykawl]

Just convienence, and ya that’s what I figured thank you