High pH / Low Alk

[griss]

Noticed tonight according to my Apex pH was 8.47. Had me questioning if I needed to calibrate my probe as I’ve historically had trouble maintaining pH. So, I tested with a Hanna and that shows 8.4.

Tested Alk with Hanna and it came out at 6.3.

Am I misremembering?? I thought high Alk = high pH and low Alk = low pH.

Thoughts?

 

[Reefing102]

That was my understanding as well. I’ll have to look as chemistry isn’t my strong suit

 

[griss]

That was my understanding as well. I’ll have to look as chemistry isn’t my strong suit

Not my strong suit either. I did some searching and only found one thread on R2R discussing it. I usually add soda ash daily to maintain my Alk but, didn't at first last night because I didn't want to push the pH higher. I added a small amount of vinegar that brought the pH down a bit and allowed me to add my usual amount of soda ash.

 

[kharmaguru]

I think ph is more connected to the CO2 levels in home aquaria. Alkalinity is the resistance to the acidity created by the presence of CO2 but not a guaranteed of any particular PH. You could have 12dkh and still have low ph because of high CO2..

 

[griss]

Thanks Sean, I knew pH was connected to CO2 but, also thought Alk buffered it. I'm perplexed by the high pH as I've always struggled to maintain it.

Now, thinking about it, we have builder grade windows in the basement (where the tank is located) the leak outside air like a sieve. So, a thousand years ago, we sealed them off with window film. We recently removed the window film so, thinking about it now, that probably resulted in less CO2 in the basement. The result is higher pH.

Now the question is, how do I raise my Alk without spiking pH too much?

 

[kharmaguru]

Yep my old house is also sieve-like. On windy days (like it is now), my ph is always jacked. As for alk adjustments. just do what you normally would . As I recall RHF says ph up to 8.7 is no cause for concern.

 

[griss]

Thanks Sean.