PH and Alk drop together?

[sandman12]

First question, does PH and Alk drop hand n hand? My PH seems to be dropping about .2 every day if I don't add anything. So I have been assuming my Alk is dropping along with it. I have been adding about 20Ml of buffer every night to keep the PH up, is this normal?

I want to start dosing kalk soon with my ATO so I am trying to stabilize my parameters first....

I usually test Cal, Alk, and Mag every 3-5 days. Mag and Cal haven't been an issue and stay relatively stable. Its just the alk that drops quickly.

TIA
James

[bertoni]

Alkalinity drops due to consumption. I'd test alkalinity every day and dose your buffer according to the alkalinity drop.

As long as the alkalinity level is in the 7-11 dKH range, the pH of a running system is set by the carbon dioxide content of the air. pH buffer products add alkalinity in various forms, and temporarily consume carbon dioxide from the water column, more or less. Aeration will bring the pH back down fairly quickly, in most casts. 2-3 hours might be a reasonable expectation.

The buffer might be pushing the alkalinity level up, so I'd be careful about that. Many tanks run at about pH 7.8 in houses with the windows shut.

[acabgd]

I wouldn't worry about pH at all, but would worry about alkalinity. You should try to kewp it very stable.

[sandman12]

2 day reading of alk
12/19 - 9.8 dkH
12/20 - 9.0 dkH

Is that drop normal and more importantly will kalk in the ATO keep up with that?

I think PH has leveled off at 8.1 via RK

[bertoni]

That drop seems reasonable to me. Kalk might be able to keep up with demand, but we'd need to know the daily evaporation rate to be sure.

[Crispy001]

What are your Ca and Mg numbers? They affect alk and must be referenced to determine if the tank is balanced.

[GreenTankCorals]

I had been struggling with Alk and pH for years since moving into a new, energy efficient house. I tried everything including adding buffers, kalk etc which in turn would affect the salinity. My corals were barely alive. I was at a point of almost leaving the hobby.

Two months ago upon someone's suggestion, I put a small amount of tank water in a jug, took it outside and aerated it. The pH before and after aeration had an almost 0.6 difference.

My skimmer air intake now is plumbed to outside air. Not only the pH and Alk are back to normal, the drop at night is only 0.1. All corals are coming back to life and I am elated.

After spending hundreds of $ on fancy equipment, test kits and chemicals, the issue turned out to be something very basic, a sealed house that recirculates air and accumulates CO2 over time.

[bertoni]

There's really no concept of balance with respect to calcium, alkalinity, and magnesium. As long as the tank is in the recommended range for each parameter, the tank should be fine.

[avandss]

Do you have a air exchange unit?

Originally Posted by GreenTankCorals

I had been struggling with Alk and pH for years since moving into a new, energy efficient house. I tried everything including adding buffers, kalk etc which in turn would affect the salinity. My corals were barely alive. I was at a point of almost leaving the hobby.

Two months ago upon someone's suggestion, I put a small amount of tank water in a jug, took it outside and aerated it. The pH before and after aeration had an almost 0.6 difference.

My skimmer air intake now is plumbed to outside air. Not only the pH and Alk are back to normal, the drop at night is only 0.1. All corals are coming back to life and I am elated.

After spending hundreds of $ on fancy equipment, test kits and chemicals, the issue turned out to be something very basic, a sealed house that recirculates air and accumulates CO2 over time.

[GreenTankCorals]

If by air excahnge unit you mean CO2 scrubber, I don't.

I considered buying it but did not want to add one more chore to the maintenance list.
I am actually quite encourged with the results of just plumbing my skimmer to the outside air.

I am running one inch PVC pipe to reduce the resistance since the distance between the skimmer and the outside is approx. 20 feet.

A good quality skimmer pulls a lot of air. I hear a suction sound on the outside end of the PVC pipe...kind of cool. I have been in the hobby for about fifteen years but underestimated the value of using outside air. I guess I am still learning.

[tmz]

First question, does PH and Alk drop hand n hand? My PH seems to be dropping about .2 every day if I don't add anything. So I have been assuming my Alk is dropping along with it. I have been adding about 20Ml of buffer every night to keep the PH up, is this normal?

Not in a closed system with variable CO2 input from the air. Dosing alk to keep pH up is futile as CO2 from the air equilibrates often leaving you with high alkalinity and low pH .The opposite can be true for high pH.

At athmospheric CO2 levels ,around 400ppm, IIRC seawater pH runs 8.0 to 8.3 at alk of around 7dkh. At 7.7 pH or lower coral skeleton can begin to dissolve; so, I would pay attention to it.

Does the one inch pipe for 20 feet sufffice to avoid any restriction in air flow to the skimmer venturi? I did a similar outside hookup with narrower tubing a few years ago with air restriction as a resuit;planned on using larger piping but went with a DIY CO2 scrubber. May want to try the outside pipe at some point; soI'm curious how it works for you.

[tmz]

FWIW, I test alk once or twice a week; it's stable at 9dkh in my system;calcium once a month holds around 480ppm; magnesium once every 2 or three months. also stable at around 1480ppm. kalk dosing and 1% daily water changes are done.
Both calcium and magnesium deplete more slowly than alk. As calcium carbonate is formed 50ppm/1dkh carbonate (alk) are used to only 20ppm calcium.

[GreenTankCorals]

Does the one inch pipe for 20 feet sufffice to avoid any restriction in air flow to the skimmer venturi?

There's no air restriction at all.

I was concerned about the resistance myself, so went ahead with the widest pvc I could install, one inch in my case. I removed the air silencer from the skimmer and plumbed the skimmer air inlet hose directly to the pvc. The quality and volume of the fine air bubbles in the skimmer has not changed. Skimmer is quiet and the outside end of the pvc has a loud suction noise. My pH is stable 24 hrs with only 0.1 drop at night.

I wish I knew about this simple improvement five years ago to save time and efforts I put into fighting the low pH and alkalinity.

[tmz]

Thanks .