Extremely high ALK consumption

[Randy Holmes-Farley Verified Community Expert]

Apologies, I was trying to explain the dose needed for PH 8 to 8.02. Which is roughly 1 hour of dosing. Historically the hour where Ph was 8 to 8.02 the dose would be 5.8ml

After I tore out the CO2 scrubber, the dose for the same PH (lights on for both) dose is 2.3 mls roughly an hour.

My total 24 hour dose has gone from 180mls to 68mls.

The goal of this post was to solve the consumption of 6dk daily.

If you are talking about pH effects, the buffering of seawater is higher at higher pH and alk and lower at lower pH and alk.

6 dKH per day in 60 gallons is a lot of material. Tens of grams of solid calcium carbonate per day. You would see it in a skimmer collection cup. That's why I do not believe it is the explanation.

 

[ReefHunter006]

If you are talking about pH effects, the buffering of seawater is higher at higher pH and alk and lower at lower pH and alk.

6 dKH per day in 60 gallons is a lot of material. Tens of grams of solid calcium carbonate per day. You would see it in a skimmer collection cup. That's why I do not believe it is the explanation.

I was referencing Alk consumption during specific PH windows because that, in my mind, should hold coral consumption of alk constant. Since corals consume more at higher PH then lower. By referencing that I needed 5.8mls historically and now only a fraction of that between PH 8 - 8.02 then I feel I have taken out the coral consumption variable.
I fully understand that there is more that goes into the consumption rates. My goal is to analyze the data I have and hopefully build a bit more understanding around what’s happening.

At a high level I can say taking the CO2 scrubber seems to have stopped any abiotic precipitation. My working theory is that the high O2 content going into the skimmer body raised the PH causing the precipitation. Maybe it isn’t in the skimmer cup.

 

[Randy Holmes-Farley Verified Community Expert]

I was referencing Alk consumption during specific PH windows because that, in my mind, should hold coral consumption of alk constant. Since corals consume more at higher PH then lower. By referencing that I needed 5.8mls historically and now only a fraction of that between PH 8 - 8.02 then I feel I have taken out the coral consumption variable.
I fully understand that there is more that goes into the consumption rates. My goal is to analyze the data I have and hopefully build a bit more understanding around what’s happening.

At a high level I can say taking the CO2 scrubber seems to have stopped any abiotic precipitation. My working theory is that the high O2 content going into the skimmer body raised the PH causing the precipitation. Maybe it isn’t in the skimmer cup.

I don't see how these conclusions follow.

You didn't hold the tank steady at pH 8.00 to 8.02 and look at alk demand in that range.

Changing pH (by removing the scrubber) reduces both biological and abiotic deposition of calcium carbonate.

The amount of alk dosing needed to cause a certain pH change has no bearing on demand or precipitation. It only depends on the alk and the pH, and the type of supplement used.

Certainly, lowering the pH is going to nearly always reduce demand, and it part of my generic suggestions on how to reduce problematic abiotic precipitation.

 

[ReefHunter006]

I don't see how these conclusions follow.

You didn't hold the tank steady at pH 8.00 to 8.02 and look at alk demand in that range.

Changing pH (by removing the scrubber) reduces both biological and abiotic deposition of calcium carbonate.

The amount of alk dosing needed to cause a certain pH change has no bearing on demand or precipitation. It only depends on the alk and the pH, and the type of supplement used.

Certainly, lowering the pH is going to nearly always reduce demand, and it part of my generic suggestions on how to reduce problematic abiotic precipitation.

You’re correct, I didn’t hold PH steady at 8 to 8.02. That was just a single data point I provided.

I don’t have the methods for keeping the reef tank at a range that confined for an extended period of time.

Instead, I compared the changes in dosing needed to maintain alkalinity hourly throughout the day.

So with the CO2 scrubber 8.0-8.02 occurs around 9am-10am and required 5.8 mls.

Without the scrubber 8.0-8.02 occurs around 11am-12pm and required 2.3.

This reduction in dosing is similar across the entire 24 hour period where I segmented the alkalinity measurement by ph ranges. At each range I am dosing roughly a 1/3rd of what I use to.

I am not looking at what amount dosed is required to change ph. Nor do I disagree that removing the co2 scrubber lowers abiotic and biological precipitation.

I am saying that without the CO2 scrubber my tank is consuming 2dkh a day, instead of 6dkh a day with the co2 scrubber.

I suspect, and I think we agree, most of that must have been abiotic precipitation.

My theory is that it was happening in the elevated oxygen of the skimmer.

Instead of approaching this as I have from the above, I may test ph of water and alkalinity in the skimmer and compare to the rest of the tank.

It seem there would be a logical connection if we are infusing co2 deficient air into the skimmer, that the Ph would be significantly higher within it and alkalinity would fall out of solution. Maybe not into the cup, but somewhere. Maybe it’s gets pumped out and settles at the bottom looking similar to brown detritus.

I don’t have the methods to isolate all the variables and I am obviously making inferences here.

I think another interesting comparison would be to compare my results with someone that uses a Y barbed fitting to pull on air from the co2 scrubber and room air.

We both agree 6dkh (if accurate) was a lot. My thoughts are if the ph of the tank now ranges from 8-8.3 instead of 8.1-8.4 (with co2 scrubber) and the demand for alkalinity is 1/3rd of what it use to be then it is possible and I suspect likely the localized PH within the skimmer was the issue.

It becomes a delivery issue to solve, which I think others have, by mixing with room air using a solenoid to avoid the issues I experience. Just a guess though.

One other side note that I just thought about regarding the skimmer collection cup. The precipitant wouldn’t necessarily need to be grams of large chunks that would be noticeable. It could be grams of small granules that bounded with organics in the skimmer before they became sizeable given the elevated amount of organics mixing in the skimmer, no?

 

[ReefHunter006]

I just wanted to let anyone that might read this looking for help that as soon as I hit a ratio of roughly 3 mg to 1 cal my daily consumption plummeted from 120mls to 60mls. Significantly reducing precipitation from what I can tell.

I started raising my magnesium 5 days ago very slowly and as soon as I hit 1360-1370 (was 1330) my daily Alk consumption reduced by half. It is the only change I’ve made this month outside of removing the scrubber. MG test kits have always been hit or miss so it’s possible my levels were lower than my trident tells me. I see no signs of coral stress and believe that somewhere in that ratio ball park is where I am going to maintain for the time being. I may tinker with adding the co2 scrubber back in the future.

 

[rhostam]

I just wanted to let anyone that might read this looking for help that as soon as I hit a ratio of roughly 3 mg to 1 cal my daily consumption plummeted from 120mls to 60mls. Significantly reducing precipitation from what I can tell.

I started raising my magnesium 5 days ago very slowly and as soon as I hit 1360-1370 (was 1330) my daily Alk consumption reduced by half. It is the only change I’ve made this month outside of removing the scrubber. MG test kits have always been hit or miss so it’s possible my levels were lower than my trident tells me. I see no signs of coral stress and believe that somewhere in that ratio ball park is where I am going to maintain for the time being. I may tinker with adding the co2 scrubber back in the future.

Thanks for the update! I think it is consistent with expectations, too.

 

[Grey Guy]

Reviving this because I need to come up with a solution.

This Alk consumption has gotten out of control to the point that it is raising salinity by .1ppt daily.

The dosing amount has gotten up to 180mls daily in less than 65 gallons of water. Net water is probably only 55ish. That equates to close to 6dkh daily and it only seems to be getting worse.

The dosing lines are placed above a power head.

I am not seeing any cementing of sand.

There is precipitation on my Nero 5s which need to be dipped in vinegar about once a week. However I don’t see the usual white precipitation. They just randomly seize up.

My simplicity pump stopped working last week. Replaced it, the pump was 1.25 years old. Hard to say if connected.
Heaters do have some white precipitation, but it doesn’t seem excessive.

SPS growth is strong,

I am not sure what to do, but it is a challenge to stay in pace with alk demand. Any suggestions or thoughts?

I would say, never trust a probe reading unless you check it regularly with a good test kit.

 

[ReefHunter006]

So I wanted to update this after attempting to use my CO2 scrubber under the higher magnesium environment. Spoiler. I regret turning the CO2 scrubber back on and I’m still recovering from it even after shutting it off.

The CO2 scrubber is anecdotally linked to the instability I experience as nothing else has changed. Worth noting that while tests kits show magnesium in the 1400-1420 range. My ICP results this month show it much higher at 1498.

I will just post the alk results and leave my interpretation to a minimum. My sps prior to turning the scrubber back on were looking very healthy and showing some of the best growth I have seen in the last 6 months. I turn the co2 scrubber on, start monitoring alk hourly to compensate for the increased demand. Over the next 24 hours things deteriorated.



Alk Results week prior.

Next picture, see if you can spot where the reactor was turned on. It began fluctuating .2 -.5 PER HOUR with little consistency so it was hard to counteract with the doser.

I am going to try an air stone with the CO2 scrubber instead of in the skimmer. I think this lends support to my theory that the localized PH in the skimmer is getting too high because of the low supply of CO2 and this causing precipitation. Tank ph never gets above 8.4 with the scrubber attached. Naturally ranges 7.9-8.25 this week.

Either way, I am confident that under my specific scenario that the co2 scrubber with my skimmer has been a direct result of my precipitation issues in the past. I hope I can find a solution that will allow me to manage my PH in the 8.1-8.3 range.

I am concerned about maintaining PH and do not intend to ignore the parameter at this time.