Effects of High pH?

[adsf430]

I use a CO2 scrubber and dose additives to keep my PH high as I notice the tank loves high PH, so when I'm away and there's no CO2 in my apartment it hits 8.8 at it's peak. My warning would be my tank consumes 3 times as much alkalinity at 8.8 as it does at 8.3. The difference is growth is easily noticeable, corals grow more in a few days with an 8.8 peak than in a month with an 8.3 peak. Not sure if it's necessary or not but I assume all the growth must lower nitrates since nutrients are likely being absorbed at an increased rate so I also feed my corals heavily.

 

[J1a]

I also have an industrial air purifier 4500 sq ft in the room. If that makes a difference

Air purifier will not change the Co2 concentration in the room, unless it's drawing fresh (then processed) air from outside.

 

[ChiCity]

Why do you say that? Aeration was important to keep pH down in my tank.

Aeration an raise or lower pH, and can actually do both in the same system at6 different times of the day, depending on whether the current pH is higher or lower than would occur by equilibrium between the alkalinity in the water and the CO2 in the air used for aeration.

i was visualizing it as aeration with an outdoor line…
which is my own imagination running wild

 

[Randy Holmes-Farley]

i was visualizing it as aeration with an outdoor line…

Even aeration with outside air can lower pH when pH is as high as the OP reports, unless he has very high alk.

 

[Aspect]

My alk is 12.5

 

[Randy Holmes-Farley]

My alk is 12.5

OK, that is very high. Higher than my recommended range of 7-11 dKH. Aeration with outside air will not lower your peak pH of 8.48 since it is close to equilibrium.

Aeration with inside air may lower it if the inside air is high in CO2, and when the pH is lower (near your low) aeration with outside air will raise it.

That all said, your current pH range is fine.

Are you adding alkalinity?

 

[Aspect]

OK, that is very high. Higher than m recommended range of 7-11 dKH. Aeration with outside air will not lower your peak pH of 8.48 since it is close to equilibrium.

Aeration with inside air may lower it if the inside air is high in CO2, and when the pH is lower (near your low) aeration with outside air will raise it.

That all said, your current pH range is fine.

Are you adding alkalinity?

Nope don't dose anything. Using reef crystals at 34.5 ppt.

 

[Randy Holmes-Farley]

Nope don't dose anything. Using reef crystals at 34.5 ppt.

OK, the demand must be very low. As coralline or other organisms start to use more alk and calcium, it will likely decline.

 

[Aspect]

OK, the demand must be very low. As coralline or other organisms start to use more alk and calcium, it will likely decline.

I have an all softy tank which are mostly frags. Only fish no calcium absorbing organisms afaik.

 

[Randy Holmes-Farley]

I have an all softy tank which are mostly frags. Only fish no calcium absorbing organisms afaik.

OK. I've seen soft coral tanks use 2 dKH per day from coralline, but I'd just keep an eye on it.

You do not dose nitrate do you? That also raises alk.

 

[Aspect]

OK. I've seen soft coral tanks use 2 dKH per day from coralline, but I'd just keep an eye on it.

You do not dose nitrate do you? That also raises alk.

Nope I don't dose anything.

 

[Gatorpa]

Figure 2 in the article linked below shows the approximate relationship between alkalinity and pH for different CO2 levels. The middle curve represents normal CO2 levels (at least when I made the graph, CO2 has risen outside since then), as one would get by equilibrating seawater with outside air.

if you start at high pH for the given alkalinity (like the blue curve), then aeration with outside or inside air will drive pH down and move horizontal along the graph to the black curve.

In your specific question (dKH of 9 = 3.2 meq/L and pH 8.3) you are just a tad to the left of the curve, and aeration with outside air tends to raise pH (though inside air with higher CO2 will often lower it). If that same 9 dKH has a pH of 8.4, then you are to the right of the black curve, and aeration will lower the pH.

The OP has a pH peak of 8.48. Aeration with inside or outside air will lower high pH unless his alkalinity is above about 4.5 meq/L = 12.6 dKH. He has a nightly minimum of pH 8.15. Aeration with present day outside air may be pretty neutral to that pH if his alk matches NSW, but may raise it a bit with normal reef tank alk, and aeration with inside air might do either, depending on the CO2 level in the home air.

pH and the Reef Aquarium - REEFEDITION

by Randy Holmes-Farley For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This article will Read more here...

www.reefedition.com

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.

Thanks for the detailed response. I appreciate it.

So simply saying outside air with a pH of 8.2-8.3 will lower the pH is not always true.
pH depends on other factors such as the CO2 in the house(big factor) and the DkH of the tank water.

It‘s really a function of all three variables so to make an accurate prediction we would need all.
Likely the inside CO2 is higher than outside (for almost all homes) .

Would you agree with that synopsis or the relationship to pH-CO2- Alk?

 

[Gatorpa]

I use a CO2 scrubber and dose additives to keep my PH high as I notice the tank loves high PH, so when I'm away and there's no CO2 in my apartment it hits 8.8 at it's peak. My warning would be my tank consumes 3 times as much alkalinity at 8.8 as it does at 8.3. The difference is growth is easily noticeable, corals grow more in a few days with an 8.8 peak than in a month with an 8.3 peak. Not sure if it's necessary or not but I assume all the growth must lower nitrates since nutrients are likely being absorbed at an increased rate so I also feed my corals heavily.

You have them on roids their are eating everything in sight.

Take care though sometimes the ULN systems can crash quick

 

[Randy Holmes-Farley]

Thanks for the detailed response. I appreciate it.

So simply saying outside air with a pH of 8.2-8.3 will lower the pH is not always true.
pH depends on other factors such as the CO2 in the house(big factor) and the DkH of the tank water.

It‘s really a function of all three variables so to make an accurate prediction we would need all.
Likely the inside CO2 is higher than outside (for almost all homes) .

Would you agree with that synopsis or the relationship to pH-CO2- Alk?

Simply put, pH is determined mathematically by the CO2 in the water and the carbonate alkalinity.

if the water is deficient in CO2 relative to the air it is being aerated with, pH will drop with aeration.

If the water has an excess of CO2 relative to the air it is being aerated with, pH will rise with aeration.

Both of these situations can happen with either inside or outside air, and it is often the case that the direction of the effect changes with the time of day as CO2 in both the water and air vary.

One does always need to know the alkalinity to know what the effect of aeration will be.

 

[Gatorpa]

Simply put, pH is determined mathematically by the CO2 in the water and the carbonate alkalinity.

if the water is deficient in CO2 relative to the air it is being aerated with, pH will drop with aeration.

If the water has an excess of CO2 relative to the air it is being aerated with, pH will rise with aeration.

Both of these situations can happen with either inside or outside air, and it is often the case that the direction of the effect changes with the time of day as CO2 in both the water and air vary.

One does always need to know the alkalinity to know what the effect of aeration will be.

TY

 

[adsf430]

You have them on roids their are eating everything in sight.

Take care though sometimes the ULN systems can crash quick

i feed the 6 fish in my tank two times a day and feed the corals a mix of reef roids/phyto/oyster feast every other day and it’s a 20 gallon Nano with about 12 gallons that’s actually water

 

[piranhaman00]

I've been pushing 8.9 w/o issues on this tank. Yes, this is true and I've double-checked my probes. YMMV.

Lol

 

[Aspect]

Lol

Is that unlikely to be true?

 

[Gatorpa]

i feed the 6 fish in my tank two times a day and feed the corals a mix of reef roids/phyto/oyster feast every other day and it’s a 20 gallon Nano with about 12 gallons that’s actually water

That’s a lot of consumption on such a small system

 

[Garf]

Is that unlikely to be true?

How do you calibrate your probe? @ pH 7 and 10? Have you done it recently.