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@BackbayReef

SCRM😎 Cool Kids🧠Reef Guru

Joined May 2026265 posts1,033 pts★5.0(2)

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Water Chemistry·Sep 10·👁 150#1

Chasing pH or Alk (or Both)?

I’ve read numerous reports and testimonials that higher pH will yield faster growth, esp SPS. That’s why I’ve been obsessed with trying different things: outside air to skimmer, CO2 scrubber, kalk, soda ash, etc. I can crank pH up to 8.4 but honestly, it’s too much effort and I don’t have the patience to keep pH up. In the end, my tank suffered. I’ve end up going back to either 2-parts or CaRx, which I can consistently keep Alkalinity stable. However, my pH is back to 8 to 8.19. Questions: what pH ranges are you guys running and what methods work well for your tanks?

— /yolo

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@ThatPoolGuy
SCRM😎 Cool KidsAquascaper
Joined Sep 202616 posts102 pts📍 Glendora, CA
Sep 10· edited Thu, Sep 10 · 10:51 PM#2
Chiming in on this… would an ac vent blowing directly in a canopy increase Ph? I’ve stopped dosing sodium carbonate took the Co2 scrubber offline, reduced Kalk dosing and ph is still high. Alk stays 7.9-7.8 Been trying to figure this out for awhile. Ever since I’ve been running the AC non stop I’ve been seeing high ph swings. Might tape off part of the vent and see what happens

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Share your experience…

@Thresher

😎 Cool Kids⛰️Aquascaper

Joined Aug 202621 posts93 pts📍 On the beach preferably

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Sep 11#3

In the past, my most stable and high ph levels were achieved using kalk and a refugium on a 24 hour light cycle. Now, I simply can't be bothered. If the tank looks nice, I'm content.

— Enjoy life, be nice!

@BackbayReef

SCRM😎 Cool Kids🧠Reef GuruOP

Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 11#4

@ThatPoolGuy wrote: Chiming in on this… would an ac vent blowing directly in a canopy increase Ph? I’ve stopped dosing sodium carbonate took the Co2 scrubber offline, reduced Kalk dosing and ph is still high. Alk stays 7.9-7.8 Been trying to figure this out for awhile. Ever since I’ve been running the AC non stop I’ve been seeing high ph swings. Might tape off part of the vent and see what happens

CO2 scrubber will boost your pH by a lot! I had it recirculating to save on media life. I even bought the 5gal media in bulk! In the end, it’s not worth the hassles so I gave the setup away. Kalk is great but I’ve had challenges dosing with a stirrer. Perhaps if you mix it in a big drum and dose, that might be more consistent— but again, too much time & effort every week / two. Good luck on the AC. Mine has been running non-stop as well and keeping the room at 77. It’s a closed system so no doubt it’s not pulling fresh air from the outside.

— /yolo

@BackbayReef

SCRM😎 Cool Kids🧠Reef GuruOP

Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 11#5

@Thresher wrote: In the past, my most stable and high ph levels were achieved using kalk and a refugium on a 24 hour light cycle. Now, I simply can't be bothered. If the tank looks nice, I'm content.

That’s where I’m at — debating between growth vs stability. Ok, sprinkle laziness in the mix! lol

— /yolo

@Ndrwater

SCRM😎 Cool Kids⚡SPS Slinger

Joined Aug 202687 posts395 pts

Sep 11#6

This is what regular fresh air will get you.. Note the very consistent wave curve on the bottom of the screenshot.. I get lots of surface agitation as well as running a big skimmer and for well over a decade I have the same wave curve in my pH readings.. There is some fluctuations of course, but stability has always been the key for me... The lower pH in the more macro curve is from keeping the house closed up because somebody decided to turn up the heater on the planet recently... It was 108° in Anaheim the other day...

— Yup....

@BackbayReef

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Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 11#7

I’m already pulling air from the outside but not budging on the big tank. I’ve just gone back to K2 kalk and soda ash — CaRx is now off. Let’s try this again 😁 So far, pH is better than yest

— /yolo

@Ndrwater

SCRM😎 Cool Kids⚡SPS Slinger

Joined Aug 202687 posts395 pts

Sep 12#8

@BackbayReef wrote: I’m already pulling air from the outside but not budging on the big tank. I’ve just gone back to K2 kalk and soda ash — CaRx is now off. Let’s try this again 😁 So far, pH is better than yest

Just looking at your and my graph, remarkably similar...

— Yup....

@BackbayReef

SCRM😎 Cool Kids🧠Reef GuruOP

Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 12#9

@Ndrwater wrote: Just looking at your and my graph, remarkably similar...

Ooh but I gotta crank this up higher. It’s very depressing for me - sorry Ben.

— /yolo

@Ndrwater

SCRM😎 Cool Kids⚡SPS Slinger

Joined Aug 202687 posts395 pts

Sep 12#10

@BackbayReef wrote: Ooh but I gotta crank this up higher. It’s very depressing for me - sorry Ben.

All good... Im just happy not killing stuff... I try not to chase numbers.. if the tank is happy, so am I...

— Yup....

@BackbayReef

SCRM😎 Cool Kids🧠Reef GuruOP

Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 12#11

@Ndrwater wrote: All good... Im just happy not killing stuff... I try not to chase numbers.. if the tank is happy, so am I...

Need for Speed, Coral Edition

— /yolo

@Drexl

SCRM😎 Cool Kids⚡SPS Slinger

Joined Aug 202688 posts364 pts📍 Porter Ranch, CA

Sep 13#12

I don't chase pH, but try to keep an even pH level 24/7. I'm not trying to grow coral for sale, so I don't need speedy growth in my corals, I need/want healthy corals, which to me, is more important. Also, the growth gains with raising your overall pH isn't that much, I believe it's barely double digits, so not really worth the squeeze. Things to consider trying to raise pH, dissolved organics will drive pH down, co2 levels in the room will do the same. So without knowing those two levels, you could be throwing money right out the window. One thing to consider with using macro algae/refugiums to increase pH or reduce pH dips at night, is the fact that when the macro algae is at rest (no photosynthesis is taking place) it's exporting co2, which contributes to pH drops. So if you're using macro algae at night and CaRx during the day, you have a double whammy of pH reduction going on. I think if you want to increase overall pH, then mitigating co2 in and around the tank and reducing dissolved organics will give better results. I run my CaRx during the day and I dose kalk at night. If I need to increase alk, then I increase both kalk amount and then keep the CaRx on a little longer or increase the co2 amount into the CaRx. I know once my demand increases that I'll have to keep the reactor on longer, which is fine and that will most likely decrease overall pH a little, which is fine by me.

— Clams and acros

@BackbayReef

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Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 13#13

Short of getting a co2 meter but I don’t think that my fish room has a co2 problem - nobody is in there except me and I’m constantly pulling in fresh air from the window fan. DOC: skimmer is running and I run UV/Ozone so good light penetration for photosynthesis. I’ve just switched to kalk dosing at night, which is more than enough for my current consumption. I will supplement with soda ash if needed. I do love the CaRx but it affects my pH a little bit, even with a second chamber. Will report back in a week to see where things stand. So far, my low is 8.10 so not bad.

— /yolo

@BackbayReef

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Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 13#14

Oh btw: I do have some Atomic Broccoli macros in the basket and they look nice under actinics! Guess I can check the refugium box? lol

— /yolo

@Drexl

SCRM😎 Cool Kids⚡SPS Slinger

Joined Aug 202688 posts364 pts📍 Porter Ranch, CA

Sep 13#15

@BackbayReef wrote: Oh btw: I do have some Atomic Broccoli macros in the basket and they look nice under actinics! Guess I can check the refugium box? lol

I have a small chunk of that in my nano system, it’s a really nice macro. It’s also a slow grower, so not much impact on co2 release, whereas something like chaetomorpha would impact co2 elevation during “off” hours.

— Clams and acros

@BackbayReef

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Joined May 2026265 posts1,033 pts★5.0(2)

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Sep 13#16

@Drexl wrote: I have a small chunk of that in my nano system, it’s a really nice macro. It’s also a slow grower, so not much impact on co2 release, whereas something like chaetomorpha would impact co2 elevation during “off” hours.

Yes - my favorite + Dragon’s Breath. Some blue codium ones look really nice as well under whites. Mine is tiny - purely for decoration in a 550gal setup. I will need 20-30% of water volume to be effective and I’m not ready to commit that much real estate into a refugium. Besides, it’s hideous when dirty. I had chaeto before in my previous tank and pruning become a pain - hence I stopped.

— /yolo

Chasing pH or Alk (or Both)?

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