Alkalinity stability? pH stability? Are they even different?

[Biologic]

What I meant was that at higher ambient CO2, more kalkwasser can be added without the pH getting as high, so the alk can rise higher.

For example, with enough CO2 in the air, you might never even get to pH 8.2 (lots of folks are in this situation), and alk might get quite high if demand is not consuming it.

Don't be misled by examples where people have so much alk demand that they even use other addition methods asc well.

The idea that one can add large amounts of kalkwasser without alk getting excessively high only applies in specific scenarios. It is not a general principle, and many folks misunderstand this.

I can attest to this. If you pH set point is set for 8.4 and you have a a lot of atmospheric CO2 in the air, you have to fight to keep it at that level. Thus the Alkalinity raises to the equilibrium in your home.

Here is a 24 hour snap shot of my home's CO2 levels. I opened up all the windows in my living room. Notice the huge drop in CO2 levels.

On my Apex, I use the Neptune DOS to dose in saturated kalkwasser from a bucket. My Neptune DOS will dose up to 3000 mL of saturated kalkwasser per 24 hours. My set point written into the DOS settings is 8.2 (through trial and error I found this to be best for me). This is largely dependent on photosynthesis in the tank and atmospheric CO2. Typically the amount dosed into the system is only maximum of 1500 mL. The point of setting it higher (3000 mL) is the DOS sets the interval and amount. I found this value to work best for me.

This is my pH in a 24 hour period. My lights turn off at 7 PM and turn on at 6:30 AM, which you can see how the pH drops ever so slightly at night.

The issue with doing alkalinity this way is that people will notice rising alkalinity as the DOS programming fights the atmospheric CO2. So one has to really find the balance of what your atmospheric conditions and tank conditions that are in the home.

Over all I really like this method as its very inexpensive. Once you find out the settings you are rocking and rolling. Alkalinity has been really stable for me. I test about once a week. Corals are happy and growing. Not out of control but growing.

I would consider a balling method in the future to better address trace element balance and magnesium, but for now this works fine. Especially on a budget.

 

[Randy Holmes-Farley]

I can attest to this. If you pH set point is set for 8.4 and you have a a lot of atmospheric CO2 in the air, you have to fight to keep it at that level. Thus the Alkalinity raises to the equilibrium in your home.

Here is a 24 hour snap shot of my home's CO2 levels. I opened up all the windows in my living room. Notice the huge drop in CO2 levels.

On my Apex, I use the Neptune DOS to dose in saturated kalkwasser from a bucket. My Neptune DOS will dose up to 3000 mL of saturated kalkwasser per 24 hours. My set point written into the DOS settings is 8.2 (through trial and error I found this to be best for me). This is largely dependent on photosynthesis in the tank and atmospheric CO2. Typically the amount dosed into the system is only maximum of 1500 mL. The point of setting it higher (3000 mL) is the DOS sets the interval and amount. I found this value to work best for me.

This is my pH in a 24 hour period. My lights turn off at 7 PM and turn on at 6:30 AM, which you can see how the pH drops ever so slightly at night.

The issue with doing alkalinity this way is that people will notice rising alkalinity as the DOS programming fights the atmospheric CO2. So one has to really find the balance of what your atmospheric conditions and tank conditions that are in the home.

Over all I really like this method as its very inexpensive. Once you find out the settings you are rocking and rolling. Alkalinity has been really stable for me. I test about once a week. Corals are happy and growing. Not out of control but growing.

I would consider a balling method in the future to better address trace element balance and magnesium, but for now this works fine. Especially on a budget.

Thanks for the info!

What alk levels does your system settle into at pH 8.2 and how high was alk getting with higher pH set points?

 

[shakey]

Thanks Randy!!
Sodium Hydroxide is pretty much MAGIC!!!
I had a Kalkwasser reactor, soda ash dosing, and recirculating CO2 scrubber on my 120. I was still struggling to keep my PH at 8.3. I switched to Sodium Hydroxide and BAM!! I have had it totally dialed in 8.3-8.35 24 hours a day!! My alkalinity is Staying in the 8.75-9.25 range also. I have disconnected Kalkwasser reactor and CO2 scrubbber. It's been about three weeks so I feel comfortable saying It"s going to keep working. I have apex Dos and Plugged it into EB8. I dose to keep it above 8.3 and I programmed the EB8 to cut off at 8.35. I dose every other hour. This is way more economical than soda ash, CO2 media, and kalkwasser too. I can see this as a huge game changer for many that are willing to take the precautions to use sodium hydroxide. All I can say is thank you again Randy and all of you on REEF2REEF!!

 

[Biologic]

Thanks for the info!

What alk levels does your system settle into at pH 8.2 and how high was alk getting with higher pH set points?

Settles in at around 8.4 (Hanna) -- it really depends on who's in the house lol. Oh and what's the weather like? Can I open the windows? That's the down fall of this method. If you want the alkalinity to never move then its not for you. I tested my 9AM readings to my 3 PM alkalinity readings and there is about a .4 dKH swing. I am honestly not really worried about swings. You should monitor alkalinity to make sure it doesn't to continue to slowly raise week by week. When I was first setting pH at 8.4, the alkalinity slowly raised to 11 dkH over a month. So people should find out what works best for them and start low at 8.2 pH.

Running theory for me -- What happens is since you are dosing mostly at night (photosythesis isn't happen) the alkalinity will always be higher in the morning and lower in the afternoon because no alkalinity is being dosed in throughout the day. This is my running theory. I wish I had an automatic alkalinity tester to really watch this, but logically this makes the most sense and my limited testing shows it.

I am still not 100% sold on this method but if achieving stable pH is the goal, then its great.

 

[Randy Holmes-Farley]

Settles in at around 8.4 (Hanna) -- it really depends on who's in the house lol. Oh and what's the weather like? Can I open the windows? That's the down fall of this method. If you want the alkalinity to never move then its not for you. I tested my 9AM readings to my 3 PM alkalinity readings and there is about a .4 dKH swing. I am honestly not really worried about swings. You should monitor alkalinity to make sure it doesn't to continue to slowly raise week by week. When I was first setting pH at 8.4, the alkalinity slowly raised to 11 dkH over a month. So people should find out what works best for them and start low at 8.2 pH.

Running theory for me -- What happens is since you are dosing mostly at night (photosythesis isn't happen) the alkalinity will always be higher in the morning and lower in the afternoon because no alkalinity is being dosed in throughout the day. This is my running theory. I wish I had an automatic alkalinity tester to really watch this, but logically this makes the most sense and my limited testing shows it.

I am still not 100% sold on this method but if achieving stable pH is the goal, then its great.

Thanks!

As an aside, I'm still very interested in data on alk consumption changes over a 24 h period in a system with a flat pH change (no day to night change) or even a reverse pH change.

The goal is to know whether the often observed alk consumption being primarily a daytime effect is mostly due to the pH being higher, or directly due to photosynthesis and internal organism effects.

 

[Randy Holmes-Farley]

Thanks Randy!!
Sodium Hydroxide is pretty much MAGIC!!!
I had a Kalkwasser reactor, soda ash dosing, and recirculating CO2 scrubber on my 120. I was still struggling to keep my PH at 8.3. I switched to Sodium Hydroxide and BAM!! I have had it totally dialed in 8.3-8.35 24 hours a day!! My alkalinity is Staying in the 8.75-9.25 range also. I have disconnected Kalkwasser reactor and CO2 scrubbber. It's been about three weeks so I feel comfortable saying It"s going to keep working. I have apex Dos and Plugged it into EB8. I dose to keep it above 8.3 and I programmed the EB8 to cut off at 8.35. I dose every other hour. This is way more economical than soda ash, CO2 media, and kalkwasser too. I can see this as a huge game changer for many that are willing to take the precautions to use sodium hydroxide. All I can say is thank you again Randy and all of you on REEF2REEF!!

You're welcome and thanks for the info!

Happy Reefing.

 

[Biologic]

Thanks!

As an aside, I'm still very interested in data on alk consumption changes over a 24 h period in a system with a flat pH change (no day to night change) or even a reverse pH change.

The goal is to know whether the often observed alk consumption being primarily a daytime effect is mostly due to the pH being higher, or directly due to photosynthesis and internal organism effects.

I thought about that too. Such a fun multidisciplinary hobby. So many mysteries still allude us.

So it would have to be a controlled set up of multiple identical tanks, with different alkalinity methods, sharing the same atmosphere?

It's so funny, I had posted a long thread with you a long time ago, and I really had to prove the whole CO2 concept to myself. I did an airstone test. Both inside and outside. That was the ah-hah! moment. I am so happy I have better grasp on the whole concept.

It's also nice to have CO2 monitoring so I can see what's going on, though its not really necessary at this point. It's just me fiddling around.

It's nice to know that I can lower CO2 in the home, which is an indicator of in-door air quality.

 

[Randy Holmes-Farley]

I thought about that too. Such a fun multidisciplinary hobby. So many mysteries still allude us.

So it would have to be a controlled set up of multiple identical tanks, with different alkalinity methods, sharing the same atmosphere?

It's so funny, I had posted a long thread with you a long time ago, and I really had to prove the whole CO2 concept to myself. I did an airstone test. Both inside and outside. That was the ah-hah! moment. I am so happy I have better grasp on the whole concept.

It's also nice to have CO2 monitoring so I can see what's going on, though its not really necessary at this point. It's just me fiddling around.

It's nice to know that I can lower CO2 in the home, which is an indicator of in-door air quality.

A tank with a reverse lit refugium that was photosynthesizing more than the main tank could do it, but beyond that, it gets technically tricky to stabilize alk and pH at the same time. It might be accomplished with a pH controlled solenoid switching between different aeration sources, coupled with an alk controller dosing an additive that didn't impact pH much. .

 

[reef_ranch]

I have been dosing kalk slurry for five or 6 months to stabilize pH at 8.3. Prior to starting, my pH would range between 8.2 - 7.8 or 7.9 and my alk was stable at 7.8-8 using a calcium reactor.
In the beginning my alk (tested every 4 hours with an Alkatronic) jumped to the mid 9s at night, swinging down into the low 8s during the day. I use a calcium reactor during the day to supplement alk and keep it from dropping even lower. The photosynthesis seems to keep the pH up enough that the kalk doser does not go on even with the addition of CO2 from the calcium reactor.
AT that time, I had introduced quite a few small SPS frags which have since grown fairly significantly, leading to.....

Here is the pH and Alk from this last week. (Ignore the 10/2 pH peak, those are false readings during a water change) PH is rock solid and Alk still moves almost a point but the midpoint is now about 8 down from above 9 attesting to the coral growth and increased demand.

I use a reverse light cycle turf scrubber (which I believe does not remove a significant amount of CO2) and a Calcium Reactor that is on from 11:00 am to 6:00 pm tuned to a level that prior to the use of kalk slurry was sufficient to maintain alk at around 8 when on 24/7.

 

[thatmanMIKEson]

Great information there! And simplified

 

[Gedxin]

Thanks!

As an aside, I'm still very interested in data on alk consumption changes over a 24 h period in a system with a flat pH change (no day to night change) or even a reverse pH change.

The goal is to know whether the often observed alk consumption being primarily a daytime effect is mostly due to the pH being higher, or directly due to photosynthesis and internal organism effects.

@jhuntstl I think your tank is a perfect candidate for this!

 

[jhuntstl]

I maintain 8.29-8.32 24/7 dosing kalkwasser(controlled by pH probe). I do have a reverse light cycle frag tank. I have a feeling you'd be more interested in a tank without a reverse light cycle, but here's some alk readings. Just recently got my kh guardian working.

You can assume the pH is 8.29-8.32 for all readings.

10/02 15:11:45 Set pH7 to 1.17 (mv)

10/02 15:20:59 Set pH4 to 2.77 (mv)

10/02 15:52:03 W.107 %0 KH :8.37

10/02 17:28:03 W.111 %0 KH :8.27

10/02 17:58:31 W.107 %0 KH :8.35

10/02 20:41:17 Save New System Environment.

10/02 21:03:19 W.112 %0 KH :8.36

10/03 01:03:18 W.110 %0 KH :8.27

10/03 05:03:19 W.110 %0 KH :8.29

10/03 09:03:21 W.113 %0 KH :8.26

10/03 13:03:17 W.108 %0 KH :8.26

10/03 17:03:17 W.106 %0 KH :8.24

10/03 21:15:21 W.113 %0 KH :8.21

10/04 01:03:21 W.113 %0 KH :8.15

10/04 05:03:17 W.107 %0 KH :7.70

10/04 09:03:20 W.112 %0 KH :7.79

10/04 13:03:21 W.112 %0 KH :7.75

10/04 16:18:43 W.113 %0 KH :7.74

10/04 17:03:18 W.111 %0 KH :7.74

10/04 21:03:22 W.114 %0 KH :7.75

10/05 01:03:19 W.113 %0 KH :7.80

10/05 05:14:46 W.116 %0 KH :7.77

10/05 09:14:50 W.111 %0 KH :7.77

10/05 13:15:45 W.111 %0 KH :7.80

10/05 16:07:52 Set pH7 to 1.36 (mv)

10/05 16:09:27 Set pH4 to 2.96 (mv)

10/05 16:35:13 W.108 %0 KH :7.77

10/05 17:14:36 W.110 %0 KH :7.71

10/05 21:08:36 W.108 %0 KH :8.26

10/06 01:15:07 W.108 %0 KH :8.11

10/06 05:03:18 W.110 %0 KH :8.18

10/06 09:03:19 W.111 %0 KH :8.15

10/06 13:03:17 W.109 %0 KH :8.21

10/06 17:03:15 W.106 %0 KH :8.24

10/06 21:03:19 W.112 %0 KH :8.29

10/07 01:03:17 W.106 %0 KH :8.30

10/07 05:03:18 W.112 %0 KH :7.54

10/07 09:03:18 W.111 %0 KH :7.60

10/07 13:03:18 W.110 %0 KH :7.60

These are my doser logs from yesterday. It's set at 15ml/min if I remember correctly. It's a total PITA to add it all up and figure how much I'm dosing per day. But could be helpful.

To paint a complete picture, I feel like I would need ambient co2 logs as well.

 

[Randy Holmes-Farley]

I maintain 8.29-8.32 24/7 dosing kalkwasser(controlled by pH probe). I do have a reverse light cycle frag tank. I have a feeling you'd be more interested in a tank without a reverse light cycle, but here's some alk readings. Just recently got my kh guardian working.

You can assume the pH is 8.29-8.32 for all readings.

10/02 15:11:45 Set pH7 to 1.17 (mv)

10/02 15:20:59 Set pH4 to 2.77 (mv)

10/02 15:52:03 W.107 %0 KH :8.37

10/02 17:28:03 W.111 %0 KH :8.27

10/02 17:58:31 W.107 %0 KH :8.35

10/02 20:41:17 Save New System Environment.

10/02 21:03:19 W.112 %0 KH :8.36

10/03 01:03:18 W.110 %0 KH :8.27

10/03 05:03:19 W.110 %0 KH :8.29

10/03 09:03:21 W.113 %0 KH :8.26

10/03 13:03:17 W.108 %0 KH :8.26

10/03 17:03:17 W.106 %0 KH :8.24

10/03 21:15:21 W.113 %0 KH :8.21

10/04 01:03:21 W.113 %0 KH :8.15

10/04 05:03:17 W.107 %0 KH :7.70

10/04 09:03:20 W.112 %0 KH :7.79

10/04 13:03:21 W.112 %0 KH :7.75

10/04 16:18:43 W.113 %0 KH :7.74

10/04 17:03:18 W.111 %0 KH :7.74

10/04 21:03:22 W.114 %0 KH :7.75

10/05 01:03:19 W.113 %0 KH :7.80

10/05 05:14:46 W.116 %0 KH :7.77

10/05 09:14:50 W.111 %0 KH :7.77

10/05 13:15:45 W.111 %0 KH :7.80

10/05 16:07:52 Set pH7 to 1.36 (mv)

10/05 16:09:27 Set pH4 to 2.96 (mv)

10/05 16:35:13 W.108 %0 KH :7.77

10/05 17:14:36 W.110 %0 KH :7.71

10/05 21:08:36 W.108 %0 KH :8.26

10/06 01:15:07 W.108 %0 KH :8.11

10/06 05:03:18 W.110 %0 KH :8.18

10/06 09:03:19 W.111 %0 KH :8.15

10/06 13:03:17 W.109 %0 KH :8.21

10/06 17:03:15 W.106 %0 KH :8.24

10/06 21:03:19 W.112 %0 KH :8.29

10/07 01:03:17 W.106 %0 KH :8.30

10/07 05:03:18 W.112 %0 KH :7.54

10/07 09:03:18 W.111 %0 KH :7.60

10/07 13:03:18 W.110 %0 KH :7.60

These are my doser logs from yesterday. It's set at 15ml/min if I remember correctly. It's a total PITA to add it all up and figure how much I'm dosing per day. But could be helpful.

To paint a complete picture, I feel like I would need ambient co2 logs as well.

Thanks. Do you have a sense of how corals responded to pH control?

Controlling the pH by alk addition means you may be dosing more alk when pH is low, not just when alk is being consumed.

That’s what makes the sort of experiment complicated, if the goal is understanding why alk is often consumed more during the day.

 

[miyags]

Anyone dose Kent Marine supper buffer-dKH for pH?? Asking because I was cleaning out closet and found an 8.8 0z container..I don't even remember why I bought this stuff. Say's It contains carbonate, bicarbonate and borate salts

 

[Randy Holmes-Farley]

Anyone dose Kent Marine supper buffer-dKH for pH?? Asking because I was cleaning out closet and found an 8.8 0z container..I don't even remember why I bought this stuff. Say's It contains carbonate, bicarbonate and borate salts

It’s not a good product to try to control pH. It’s pH boost is lower than a pure carbonate or hydroxide product.

I don’t even like it as an alk supplement due to the borate, but if you already have it, it is likely ok.

 

[jhuntstl]

Thanks. Do you have a sense of how corals responded to pH control?

Controlling the pH by alk addition means you may be dosing more alk when pH is low, not just when alk is being consumed.

That’s what makes the sort of experiment complicated, if the goal is understanding why alk is often consumed more during the day.

I was using All-for-Reef before with some supplemental kalk to boost pH. The goal was to maintain around 8.5dkh at the time. Wish I could say I chased a specific alkalinity with only kalkwasser for a more direct comparison. When I made the switch to full kalkwasser, I pretty quickly transitioned into keeping pH at 8.3 and letting alk do it's thing.

Response has been positive overall. I mainly have acros, but growth across the board significantly improved. I did have some issues a few months in with deficiencies. Specifically magnesium, potassium, and some minor traces. I lost some small maricultured acro frags that had otherwise been encrusting very quickly. I've since put Mg on a doser and I test K every week or so. I'm also experimenting with a very low dose of trace elements. Keeping up No3 and Po4 has been a challenge as well, but I now dose them as well. I don't think these are specific symptoms of maintaining 8.3, but perhaps they are exacerbated a bit?

Since I now have the KH Guardian working, I may experiment with dosing based on alkalinity. As you can see my alk swings dosing based on pH are pretty minimal(imo). But I am thinking it could be worth stabilizing alk at let's say 7.5 and allowing for a small pH swing. Maybe 8.2-8.4. Just throwing out numbers. One of my biggest fears of dosing based on pH is co2 levels. If I was entertaining 10 people in my modest 900sqft home, I'd imagine kalkwasser would not stop dosing until everyone left. Alk would spike. Would this be an issue? Hard to say. I do think there's a balance I could achieve in that situation with the help of a controller. One that would not allow pH to drop too low while keeping alk from spiking too high. Any thoughts on a situation like that?

 

[Miami Reef]

The goal is to know whether the often observed alk consumption being primarily a daytime effect is mostly due to the pH being higher, or directly due to photosynthesis and internal organism effects.

I believe that alkalinity consumption is tied to photosynthesis.

1) I increased my photoperiod and I saw my alkalinity consumption increase.

2) My alkalinity is currently 9dkh and my pH went as high as 8.4 for 3 hours before lights went out. It’s currently 7:30am (8 hours after lights turned off). It’s still night time for the tank and my pH is currently 8.2. I do not dose any alkalinity during the night and my alkalinity stays the same level as the time I tested near the lights off.

It wouldn’t make sense for alkalinity consumption to completely halt at a pH of 8.2.

What do you think?

 

[las]

Given a choice between a ph level that stays super stable at 8.02-8.06 during the day or, one that ranges from 8.1-8.4 during the day, which option would be the most beneficial for corals. I realize staility is key. But how key is it compared to achieving better ph levels but much more volatile?

 

[las]

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[thatmanMIKEson]

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