pH won't go over 7.7

[rockstarta78]

Watch this around 1 minute he begins to talk about pH. This video is VERY important.

Thank you for the video. It makes sense now why I have lower pH.

 

[rockstarta78]

I think I am going to implement a CO2 scrubber once I see how the new Kalk dripping is effecting the overall pH of the tank. Once I get a good read on the pH over next few weeks, I can make a better decision on adding the CO2 scrubber.

 

[Randy Holmes-Farley Verified Community Expert]

That sounds like a fine plan.

I discuss pH issues here:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

 

[rockstarta78]

As always thank you so much for your help @Randy Holmes-Farley That document is very helpful.

 

[rob safron]

I have a CO2 scrubber as well as have that line outside the house. I dose Kalk in my tipoff water and still my pH at night/ early morning is 7.2 and high of 8.02. I give up.

 

[rob safron]

I mean 7.72

 

[Andrewalex11]

I have a CO2 scrubber as well as have that line outside the house. I dose Kalk in my tipoff water and still my pH at night/ early morning is 7.2 and high of 8.02. I give up.

8.02 is fine, that's within the 7.8 - 8.3 range you want. What's your Alk at?

 

[rob safron]

I keep it at 7.5, ultra low nutrient. I worry more about the low of 7.72.

 

[rockstarta78]

I am tempted to push my Alk to 10 or even 12 just to see how the pH would react. But I don't want to tempts fate. I have had many issues with this tank, so why rock the boat. Plus the Alk swing won't be good for the corals. But it'd be interesting to see the result.

 

[Bunnee911]

I have that exact ph pen. It tends to drift. You can purchase solutions to check it with. Try horticulture.

 

[Randy Holmes-Farley Verified Community Expert]

I am tempted to push my Alk to 10 or even 12 just to see how the pH would react. But I don't want to tempts fate. I have had many issues with this tank, so why rock the boat. Plus the Alk swing won't be good for the corals. But it'd be interesting to see the result.

There are two effects from raising alk. One is the effect of the alk itself, and the other is from the additives used.

The rise from 8 dKH to 10 dKH (ignoring the additives used) will effectively boost the pH from, say, 8.0 to 8.1.

 

[rockstarta78]

There are two effects from raising alk. One is the effect of the alk itself, and the other is from the additives used.

The rise from 8 dKH to 10 dKH (ignoring the additives used) will effectively boost the pH from, say, 8.0 to 8.1.

Thank you Randy for the actual number. My fear is, with the alk swing how the corals are going to react.

 

[rockstarta78]

I have that exact ph pen. It tends to drift. You can purchase solutions to check it with. Try horticulture.

Ok good to know. I will recalibrate the darn thing.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you Randy for the actual number. My fear is, with the alk swing how the corals are going to react.

If you have low nutrients, I'd focus more on now allowing the alk to get too high. :)

 

[dangros]

@Randy Holmes-Farley , is there a chart to look up alk to pH values (assuming calcium is stable at ~420)?
Also, what is more important? The upper range or lower range w/the pH day to night swings?

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley , is there a chart to look up alk to pH values (assuming calcium is stable at ~420)?
Also, what is more important? The upper range or lower range w/the pH day to night swings?

IMO, the extremes of pH are important if they drop below 7.8 (harder for corals to form skeletons) or above 8.6 (more abiotic precipitation on pumps, etc.)

Here's a graph I made of the rough effect, but a doubling of the alkalinity will generally lead to about a 0.3 pH boost at equilibrium with the air.

http://www.reefedition.com/ph-and-the-reef-aquarium/

Figure 2. The relationship between alkalinity and pH in seawater with normal carbon dioxide levels (black), excess carbon dioxide (purple) and deficient carbon dioxide (blue). The green area represents normal seawater.

 

[dangros]

Unfortunately, we may have to raise the "normal" line given our current lack of environmental policies :(

Not to hijack this thread but for some reason, my pH started to drop lower at nights and range similar to the OP's. The highs also dropped but not as much as the lows. Recently, I replaced my Kessils with GHLs which have significantly more power so I took one of the Kessils and replaced my fuge lights to speed up cheato growth. It's working but the pH only improved a bit. Having said that, my corals are growing way better than before so I'm not AS concerned. This weekend, I will take a powerhead and blast everything around in the tank hoping to capture any loose detritus, etc that may not be getting caught by my automatic water changes. My Alk dropped also but it's now back up to 8.0 and the pH has not improved much.

 

[Reef 450]