High Alk & Low PH? Low Alk & high PH.. Im confused

[Sdot]

Help, im confused by the following result and im hoping you could help me clarify. With ATI essentials.. i've noticed if my DKH is 7.1 ( 7.1 = Apex Trident, ICP test 7.4 DKH) my PH gets to around 8.25. If i raise my DKH to 7.4 (Trident) or more it lowers my PH to around 8.08, any reason why? I thought the opposite would be the case. Is there any problem keeping my alk at 7.1 (Trident / ICP 7.3) ? Thanks. Please see below chart, PH is Orange and ALK is blue.

 

[AllSignsPointToFish]

I've experienced something very similar recently. When my tank ran around a dKH of 10, the pH struggled to stay in the 8-8.2 range. When I lowered the alkalinity to around 8, the pH typically runs 8.1-8.3.

I wonder if the higher alkalinity encourages more CO2 scrubbing from the surroundings?

Full disclosure is that I'm in the middle of testing how my tank reacts to a limewater drip. While the overall pH swings will be lessened by continuous limewater addition, it appears that the baseline pH has also risen with lower sustained alkalinity levels.

 

[Sdot]

I've experienced something very similar recently. When my tank ran around a dKH of 10, the pH struggled to stay in the 8-8.2 range. When I lowered the alkalinity to around 8, the pH typically runs 8.1-8.3.

I wonder if the higher alkalinity encourages more CO2 scrubbing from the surroundings?

Full disclosure is that I'm in the middle of testing how my tank reacts to a limewater drip. While the overall pH swings will be lessened by continuous limewater addition, it appears that the baseline pH has also risen with lower sustained alkalinity levels.

Please keep me updated on the Lime water drip.

 

[AllSignsPointToFish]

Please keep me updated on the Lime water drip.

So far, it's going very well although it's a pain to keep up. The tank has responded very well to the lowered alkalinity, and I've been happy with the rate of addition essentially matching the evaporation rate so that the salinity is constant.

 

[AllSignsPointToFish]

Right now, calcium is stable at 420 ppm, alkalinity is 7.9-8.1 dKH, and salinity is constant at 1.026.

 

[Sdot]

Right now, calcium is stable at 420 ppm, alkalinity is 7.9-8.1 dKH, and salinity is constant at 1.026.

I think my goal is to keep my ALK around 7.3 DKH (ICP) or 7.1 - 7.2 DKH (Trident). I think i get better growth with the higher PH.

 

[AllSignsPointToFish]

I think my goal is to keep my ALK around 7.3 DKH (ICP) or 7.1 - 7.2 DKH (Trident). I think i get better growth with the higher PH.

Well, seawater is around 7dKH, so there's something to be said about replicating mother nature

 

[Sdot]

Well, seawater is around 7dKH, so there's something to be said about replicating mother nature

Very true

 

[AllSignsPointToFish]

Certainly my corals seemed to very quickly appreciate the reduction in overall alkalinity.

 

[Sdot]

Certainly my corals seemed to very quickly appreciate the reduction in overall alkalinity.

That's refreshing...most folks are pushing alk as high as possible....