Another dosing help thread..

[Miami Reef]

I show the details of how I did it here, but it’s not obvious how to do that easily. I did it using a spread sheet.

https://reefs.com/magazine/chemistry-and-the-aquarium-the-relationship-between-alkalinity-and-ph/
And one can just sight along Figure 1 in that article.

But what I did here for a small change in alk is look at the change in the log of the pH. It’s a good approximation for a small alk change.

Log 9 - log 8 = 0.05 or a 0.05 change in pH

Looking at Figure 1 in the graph one can see it is roughly accurate even for a bigger change.

Log 3 - log2 =0.176

From Figure 1 we can see that corresponds to about

8.33 - 8.18 =0.15

So it’s close enough for this sort of purpose.

Wow. I bookmarked it. I’ll quote this if I need it as a reference when helping others. This is excellent.

I have another pH related question. Not sure if I should make another thread or just continue it here.

I appreciate you so much for teaching me different chemistry concepts.

 

[Randy Holmes-Farley Verified Community Expert]

I have another pH related question. Not sure if I should make another thread or just continue it here.

Fire away!

 

[Miami Reef]

Fire away!

Excellent. Thank you.

People tout refugiums and algae-based filtration as effective pH increasers.

But do they realize how much algae is actually required to achieving that effect? Is there a calculation describing how much algae is required?

It’s also a little counterproductive because the algae will release (the same?) CO2 that’s consumed during the photoperiod at night.

It’s good for stabilizing pH when lit reversely, that part I got.

Are there any studies on this? It’s going to be in a section of a pending article of mine, and I’d like to have references that I can link/quote.

 

[vandy]

I show the details of how I did it here, but it’s not obvious how to do that easily. I did it using a spread sheet.

https://reefs.com/magazine/chemistry-and-the-aquarium-the-relationship-between-alkalinity-and-ph/
And one can just sight along Figure 1 in that article.

But what I did here for a small change in alk is look at the change in the log of the pH. It’s a good approximation for a small alk change.

Log 9 - log 8 = 0.05 or a 0.05 change in pH

Looking at Figure 1 in the graph one can see it is roughly accurate even for a bigger change.

Log 3 - log2 =0.176

From Figure 1 we can see that corresponds to about

8.33 - 8.18 =0.15

So it’s close enough for this sort of purpose.

Thanks for the math on this. Looking at the graph, why isn't alk of 3.5 meq/l (~10dkh?) more popular of a value to run? I've seen ~8-8.5dkh touted over and over again as target number to hit, and i've been running it for years. Especially if youre trying to maximize sps growth

 

[Randy Holmes-Farley Verified Community Expert]

I’ve not seen any studies nor is there a way to calculate easily, but they are very effective and do not release most of the CO2 consumed.

A rough way to judge is the amount of dry tissue mass added daily. If the refugium added the same amount of tissue as corals and algae in the main tank, it’s ph rise when lit would be similar.
I think in my early stage tank the refugium is a much bigger consumer of CO2 than is the main tank.

 

[Miami Reef]

Thanks for the math on this. Looking at the graph, why isn't alk of 3.5 meq/l (~10dkh?) more popular of a value to run? I've seen ~8-8.5dkh touted over and over again as target number to hit, and i've been running it for years. Especially if youre trying to maximize sps growth

Can I give my opinion?

Why do most people keep alk at 8 dKH?
Because it’s safe. Many people have had fantastic results with it, and many people don’t want to go against the grain or try out new waters.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for the math on this. Looking at the graph, why isn't alk of 3.5 meq/l (~10dkh?) more popular of a value to run? I've seen ~8-8.5dkh touted over and over again as target number to hit, and i've been running it for years. Especially if youre trying to maximize sps growth

I recommend 7-11 dKH, and do not think that 7 or 8 or 9 or 10 or 11 dKH is the clear best. There are pros and cons. I’m targeting about 9 dKH.

Coral growth rates and forms, colors, matching the new salt water, and other factors all go into folks decisions, and it is often based on their previous experiences rather than published data that others also see.

 

[vandy]

Can I give my opinion?

Why do most people keep alk at 8 dKH?
Because it’s safe. Many people have had fantastic results with it, and many people don’t want to go against the grain or try out new waters.

I recommend 7-11 dKH, and do not think that 7 or 8 or 9 or 10 or 11 dKH is the clear best. There are pros and cons. I’m targeting about 9 dKH.

Coral growth rates and forms, colors, matching the new salt water, and other factors all go into folks decisions, and it is often based on their previous experiences rather than published data that others also see.

Copy. I'll plan on raising to 10 over the course of the next few weeks. Thanks for the help!

 

[Miami Reef]

I’ve not seen any studies nor is there a way to calculate easily, but they are very effective and do not release most of the CO2 consumed.

A rough way to judge is the amount of dry tissue mass added daily. If the refugium added the same amount of tissue as corals and algae in the main tank, it’s ph rise when lit would be similar.
I think in my early stage tank the refugium is a much bigger consumer of CO2 than is the main tank.

Thank you very much. That’s good to know. Algae filtration isn’t the primary scope, but a small section does mention it. I’ll try to gather as much info as I can for it.

I think one of the challenging concepts for me to understand is the CO2 equilibrium aspect. Seeing how the equation reverses when removing CO2 is fascinating, but kind of confusing.

And then I read that (OH)2 mixes with hydrogen to make water? That sound doesn’t right…I’d assume it combines with CO2.

Anyway, it’s one of the most interesting articles I’ve worked on. I’m still long ways ahead to finishing it. Now’s the research phase.

 

[rishma]

Excellent. Thank you.

People tout refugiums and algae-based filtration as effective pH increasers.

But do they realize how much algae is actually required to achieving that effect? Is there a calculation describing how much algae is required?

It’s also a little counterproductive because the algae will release (the same?) CO2 that’s consumed during the photoperiod at night.

It’s good for stabilizing pH when lit reversely, that part I got.

Are there any studies on this? It’s going to be in a section of a pending article of mine, and I’d like to have references that I can link/quote.

I have an observation to share that relates to this.

I noticed a pattern for a long time but only recently realized what what happening. My pH tends to drift higher the month I am traveling. Then when I get home it takes a step change downward and starts drifting up again but doesn’t get quite as high as when I am away.

8.35-8.45 is normal. The first week I am home it tends drop to 8.3-8.35, then it slowly works it way back to the normal range but gets even higher after I leave to travel again.

I thought the change was caused by my water change when I get home, but I realized that it’s actually the algae growth. I do a water change before leaving and I don’t see a big change.

The tank doesn’t get cleaned when I am gone. I usually come home to pretty green glass and a little hair algae in the pumps. I give the tank a good cleaning and change water. Recently I came home and didn’t have time to mix and change water so I scrubbed things down and ran a filter sock. The pH followed the same pattern and as algae re-established the pH began its steady increase again.

When I am home, the pH is a few 100ths lower than the peak when I am away. I clean the glass regularly when I am home.

It’s mostly microalgae and not a lot compared to what I think a typical refugium has. Algae growth in the tank seems to contribute 0.05-0.1 pH peak. It’s a big change for what I think of as not a ton of algae.

 

[scotty333]

Why not try this
Take a ltr of tank or mixed water check the ph and kh and add kh buffer to raise it to 12 then check ph again
I’m going to do it later too

 

[Miami Reef]

I have an observation to share that relates to this.

I noticed a pattern for a long time but only recently realized what what happening. My pH tends to drift higher the month I am traveling. Then when I get home it takes a step change downward and starts drifting up again but doesn’t get quite as high as when I am away.

8.35-8.45 is normal. The first week I am home it tends drop to 8.3-8.35, then it slowly works it way back to the normal range but gets even higher after I leave to travel again.

I thought the change was caused by my water change when I get home, but I realized that it’s actually the algae growth. I do a water change before leaving and I don’t see a big change.

The tank doesn’t get cleaned when I am gone. I usually come home to pretty green glass and a little hair algae in the pumps. I give the tank a good cleaning and change water. Recently I came home and didn’t have time to mix and change water so I scrubbed things down and ran a filter sock. The pH followed the same pattern and as algae re-established the pH began its steady increase again.

When I am home, the pH is a few 100ths lower than the peak when I am away. I clean the glass regularly when I am home.

It’s mostly microalgae and not a lot compared to what I think a typical refugium has. Algae growth in the tank seems to contribute 0.05-0.1 pH peak. It’s a big change for what I think of as not a ton of algae.

I’m not doubting it as a possibility, but it’s actually well documented that pH increases when people leave for vacation because there is less CO2 in the air.

When you leave, is the house mainly empty or is there a lot of family still residing?

 

[Randy Holmes-Farley Verified Community Expert]

I have an observation to share that relates to this.

I noticed a pattern for a long time but only recently realized what what happening. My pH tends to drift higher the month I am traveling. Then when I get home it takes a step change downward and starts drifting up again but doesn’t get quite as high as when I am away.

8.35-8.45 is normal. The first week I am home it tends drop to 8.3-8.35, then it slowly works it way back to the normal range but gets even higher after I leave to travel again.

I thought the change was caused by my water change when I get home, but I realized that it’s actually the algae growth. I do a water change before leaving and I don’t see a big change.

The tank doesn’t get cleaned when I am gone. I usually come home to pretty green glass and a little hair algae in the pumps. I give the tank a good cleaning and change water. Recently I came home and didn’t have time to mix and change water so I scrubbed things down and ran a filter sock. The pH followed the same pattern and as algae re-established the pH began its steady increase again.

When I am home, the pH is a few 100ths lower than the peak when I am away. I clean the glass regularly when I am home.

It’s mostly microalgae and not a lot compared to what I think a typical refugium has. Algae growth in the tank seems to contribute 0.05-0.1 pH peak. It’s a big change for what I think of as not a ton of algae.

Certainly seems plausible to me. There is a lot of algae surface area covering the glass.

 

[rishma]

I’m not doubting it as a possibility, but it’s actually well documented that pH increases when people leave for vacation because there is less CO2 in the air.

When you leave, is the house mainly empty or is there a lot of family still residing?

It’s not that. The house is full of people when I am gone, I travel for work, family is home.

 

[Miami Reef]

It’s not that. The house is full of people when I am gone, I travel for work, family is home.

Cool! Thanks for the data point! I’m glad I asked this question.

 

[rishma]

Certainly seems plausible to me. There is a lot of algae surface area covering the glass.

I cannot imagine how it’s useful info, but I did think it was interesting.

 

[Macdaddynick1]

Hey all! I'm looking for a little critiquing of my dosing regime. The goal of this thread is to eventually "chase" ph to the 8.1-8.3 range. Setting the stage: my tank is a 100gal IM 100INT, roughly 9 months old, and heavily leaning towards an SPS tank with 15+ "mini colony" sized pieces (>8"). The tank also has tons of LPS and coralline growing like crazy. All my SPS have been growing great over the last few months, but I think they will really excel under the slightly higher ph.

Current ph range: 7.75-8.0. Some days even lower than 7.75. Assuming ~.5 probe inaccuracy

My current dosing scheme:
Calcium reactor @ 6.5ph being dosed 24/7 by a doser running 120ml/min.
Full saturation kalkwasser dosed via kalk stirrer. 4400ml/day, dosing split into 48 times throughout the day
Sodium Hydroxide - dosing 100ml/day split into two dosing periods: 60ml in the morning (dosed 8am-10:30am), 40ml in the evening (11pm-3am / 10ml/hr). Mixed to the same concentration as the soda ash recipe.

I also have a CO2 detector right next to my tank. I know these might not be the most accurate, but it consistently reads 402-420ppm throughout the day. I keep a window open and pump fresh air towards the tank. Just in case, I also have a CO2 scrubber on my skimmer.

To offset the ph depression from the calcium reactor, I run it through a 2nd chamber, and I also put the output of the dosing line into a cup that has an air bubbler, which overflows into the sump.

Anybody have any other recommendations to raise my PH? I'm open to adjusting any ratio that I am currently using. I would like to try to avoid using an algae reactor, as my nutrients are pretty dialed with my feeding regime.

The sodium hydroxide dosing in the morning before the lights turn on gets me to my max PH faster, but still cant climb over to the 8.1 territory.

Any help would be greatly appreciated!

Have you tried dosing your CaRx effluent directly into the skimmer output? IIRC it bumped my ph by around .2 overall when I started. Kinda like in the photo. Another .2 I saw from my all raising to 10 dkh. I’m waiting for a new ph probe so I don’t have a graph for you atm.

 

[vandy]

Have you tried dosing your CaRx effluent directly into the skimmer output? IIRC it bumped my ph by around .2 overall when I started. Kinda like in the photo. Another .2 I saw from my all raising to 10 dkh. I’m waiting for a new ph probe so I don’t have a graph for you atm.

That was an option I considered as well. Ended up dripping my effluent into a plastic Quart cup with an air stone in it. It’s given me a .05ph boost from where my ph used to be. .2 is pretty significant so I might switch to what you do

 

[Macdaddynick1]

That was an option I considered as well. Ended up dripping my effluent into a plastic Quart cup with an air stone in it. It’s given me a .05ph boost from where my ph used to be. .2 is pretty significant so I might switch to what you do

I don’t dose Kalk. So you might want to check to see if your results would be comparable to what you’re doing now.

 

[vandy]

Reporting back in after 2 weeks to show my findings if anyone stumbles across this thread in the future. Implementing the following has helped me achieve a new ph range of 8.25 during the day, 7.9 at night:

1. Running my effluent line through the top of my skimmer lid. Not sure my effluent was getting enough contact time with the air stone in a cup. Plus side of this, i'm no longer getting salt spray from the air stone bubbles. See pictures above by @Macdaddynick1 for reference.

2. Raising my alk from ~7.5 to 10

3. Only dosing NaOH during the morning and throughout the day when the lights are on, vs in the morning before the lights turn on, and right after lights turn off. Judging from my graphs, I have a much more consistent rise in ph versus a drastic spike, then slowly dropping over time.


I'm happy where i'm sitting right now, but I will continue to tweak this little by little to squeeze more acro growth. Seeing substantial growth after these two weeks already.