PH: 9. Corals closing

Bbio

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Half of my corals have closed. Everything has looked fine parameter wise for months and over the past few weeks, things are closing and I finally got a PH meter and my pH is 9!!!

Tank is 150g 5 months old.


My RODI water is reading 9 also and my tap water is reading 8.3.


20260407_214107_81B3D367-C3D2-45A8-884C-DAC391FF9638.png

I have been having bottoming out nitrates and phosphates and lowering dKH so I’ve been dosing neonitro, neophos, and tropic marin carbo calcium.
 

That Crusso Kid

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Half of my corals have closed. Everything has looked fine parameter wise for months and over the past few weeks, things are closing and I finally got a PH meter and my pH is 9!!!

Tank is 150g 5 months old.


My RODI water is reading 9 also and my tap water is reading 8.3.


20260407_214107_81B3D367-C3D2-45A8-884C-DAC391FF9638.png

I have been having bottoming out nitrates and phosphates and lowering dKH so I’ve been dosing neonitro, neophos, and tropic marin carbo calcium.
If your RODI water is measuring a pH of 9 then it is time to change your resin.
 

ReneReef

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How do you measure pH?
When in the light cycle do you measure?

A pH of 9 while dosing nothing that increases it is very unlikely.
 

That Crusso Kid

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How do you measure pH?
When in the light cycle do you measure?

A pH of 9 while dosing nothing that increases it is very unlikely.
I'm not so sure I follow you, but, like I said, if the pH of the water coming out of your RODI is 9, then you need to change your DI resin.
 

ReneReef

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I'm not so sure I follow you, but, like I said, if the pH of the water coming out of your RODI is 9, then you need to change your DI resin.
Luckily you don't need to follow me, as I was responding to the OP's opening post.
So, you'll have to wait how this topic evolves and see if you can catch up at some point. Good luck.
 

That Crusso Kid

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Luckily you don't need to follow me, as I was responding to the OP's opening post.
So, you'll have to wait how this topic evolves and see if you can catch up at some point. Good luck.
Good catch! I thought I was replying to the OP, hence the confusion.

And good luck to you too!
 

Fish Fan

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mcarroll

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Half of my corals have closed. Everything has looked fine parameter wise for months and over the past few weeks, things are closing and I finally got a PH meter and my pH is 9!!!

Tank is 150g 5 months old.
So tank is brand new.
My RODI water is reading 9 also and my tap water is reading 8.3.


20260407_214107_81B3D367-C3D2-45A8-884C-DAC391FF9638.png

I have been having bottoming out nitrates and phosphates and lowering dKH so I’ve been dosing neonitro, neophos, and tropic marin carbo calcium.
Parameters were aparently not fine for months if you've been bottoming out nutrients and messing with alkalinity, right?

Double check the pH pen's calibration and make sure you can get sane readings on a known source like your tap water (usually 7) or freshly mixed seawater (usually 8). Look up your water report, or call your water company, to find out what the tapwater's pH should be. A calibration solution can be used, if necessary, but using something you already have is nice.

Seems like your magnesium is pretty low too...not a coral issue, but makes me wonder about testing error and the salt mix you are using. Did you remix it before scooping out of it? Ca, alk and salinity seem OK. NO3 and PO4 are both still on the low side if you are having coral issues. Raise PO4 to 0.10 ppm and hold it there. As long as 5 ppm is as low as NO3 goes, that's OK, but if you see it lower than that, use a higher target for dosing. You having nothing to worry about from "overdoing it", so dosing up to 10 or 15 ppm would be fine if it seems necessary to get the minimum level you want (and not lower).
 

Randy Holmes-Farley

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Seawater will not be stable at pH 9. That value is almost certainly test error, and if somehow was accurate, simple aeration will rapidly lower it.

The ro/di is never worth measuring for pH since, as noted above, a normal pH meter cannot accurately read that pH due to the very low ionic strength.
 

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