Skimmer + Co2 scrubber no alk change

[Lifeguard]

Hi can anyone give me some advice about my skimmer with co2 scrubber, my question is - when my skimmer and the co2 scrubber is on, the alkalinity stays the same all the time but last week I had to dose flux rx, so I had to turn my skimmer off for 3 days, my alk was going down by 0.2 to 0.3 each day and after 3 days i turned my skimmer back on again, my alk stay same and doesn't change or fluctuate does this seem like it could be the coral isnt growing? Before i added the co2 scrubber to my system the alk was going down? Any advice?

 

[CivicS14]

what does a co2 scrubber have anything to do with your alk? am I missing something? co2 scrubbers are meant to increase the PH in your tank.

 

[((FORDTECH))]

And by increasing ph then alk consumption will go up causing you alk value to go down.

 

[Futuretotm]

What @CivicS14 said, co2 scrubber/skimmer will raise pH
Yes pH is a cousin of Alk, but that doesn't mean alk will rise with pH.

 

[HuduVudu]

what does a co2 scrubber have anything to do with your alk? am I missing something? co2 scrubbers are meant to increase the PH in your tank.

Here is how CO2 works in your tank. The chemical formula for carbonic acid is H2CO3. A portion of CO2 that goes into your tank creates carbonic acid through this equation H20 + CO2 -> H2CO3. This is a weak acid and dissassociates in your tank as 2H+ (acid) and CO3-- (carbonate or alkalinity NOTE: they are not the same but used interchangebly). What this means is that the PH goes down in the presence of the weak acid (2H+) BUT there is measurable (read testable) CO3-- (carbonate/alkalinity) in the tank. This is just the nature of how this acid works. When you remove the excess CO2 through areation then the acid goes away and PH will go up. Also since the carbonate is no longer in the water the testable alkalinity will also go down.

 

[Lifeguard]

what does a co2 scrubber have anything to do with your alk? am I missing something? co2 scrubbers are meant to increase the PH in your tank.

I know the scrubber raises the Ph. Im asking if anybody had some advise as when i use my co2 scrubber alk stays the same and when I disconnect the scrubber the alk goes down.

 

[((FORDTECH))]

I know the scrubber raises the Ph. Im asking if anybody had some advise as when i use my co2 scrubber alk stays the same and when I disconnect the scrubber the alk goes down.

Very strange because like I said co2 scrubber raises ph which in turn raise if ph drives the corals to use more alk which this would lower alk when scrubber is on. You are experiencing the opposite so this is very strange

 

[((FORDTECH))]

you never posted a before and after number of ph when using scrubber. Could it be that your ph is going down with scrubber hooked up so by removing scrubber your ph goes back up then causing corals to use more alk because ph goes up with your scrubber off?

 

[((FORDTECH))]

Ph goes up corals use more alk due to higher ph there fore your alk number goes down. This is normal operation

 

[Lifeguard]

What @CivicS14 said, co2 scrubber/skimmer will raise pH
Yes pH is a cousin of Alk, but that doesn't mean alk will rise with pH.

Yeah i know and that's why i added the co2 scrubber to raise my pH and it did raise it. Yeah im aware they are related but im asking why my alk is not going down? is it because my corals are not using the alk?

 

[HuduVudu]

Yeah i know and that's why i added the co2 scrubber to raise my pH and it did raise it. Yeah im aware they are related but im asking why my alk is not going down? is it because my corals are not using the alk?

Biological filters acidify the water consuming alk in the process. Corals also consume alk. There are other processes that acidify the water and consume alkalinty. If their accumulated demand is low then the alk will go down slowly. So alk consumption is demand dependant.

CO2 in the home aquarium "adds" carbonate. This comes up on our tests. It is confusing because it can "subtract" carbonate just a quickly. It is best to get the CO2 to a steady level and then watch the alk based on that.

 

[Lifeguard]

you never posted a before and after number of ph when using scrubber. Could it be that your ph is going down with scrubber hooked up so by removing scrubber your ph goes back up then causing corals to use more alk because ph goes up with your scrubber off?

Before i added the co2 scrubber my pH was between 7.8 and 8 and after I added the co2 scrubber my pH is between 8.3 and 8.4.i also cant see good growth with the corals.

 

[Randy Holmes-Farley]

Yeah i know and that's why i added the co2 scrubber to raise my pH and it did raise it. Yeah im aware they are related but im asking why my alk is not going down? is it because my corals are not using the alk?

Skimmers do a lot more than aerate the water. They remove organics and toxins and other things.

I'm not sure why the alk change was different. I do not know of any specific reason it would deplete more slowly if pH did rise.

 

[Randy Holmes-Farley]

Are you recirculating the skimmer air, or is it a single pass?

 

[Lifeguard]

Skimmers do a lot more than aerate the water. They remove organics and toxins and other things.

I'm not sure why the alk change was different. I do not know of any specific reason it would deplete more slowly if pH did rise.

Will i be better of without scrubber

Are you recirculating the skimmer air, or is it a single pass?

Its Just the single pass.

 

[Randy Holmes-Farley]

Will i be better of without scrubber
Its Just the single pass.

I would judge based on how corals look or grow after a few weeks, not based on alk demand.

Single pass rules out problems with O2 that recirculating might be increasing.

Does the skimmer output seems to have altered in any way? A scrubber might inhibit air flow and alter skimming that way..

 

[Lifeguard]

I would judge based on how corals look or grow after a few weeks, not based on alk demand.

Single pass rules out problems with O2 that recirculating might be increasing.

Does the skimmer output seems to have altered in any way? A scrubber might inhibit air flow and alter skimming that way..

Went we went on holiday for 4wks the tank was being looked after by family with instructions and i was overseeing from abroad. I turned the skimmer off before leaving, and when we came back I had visible coral growth. Yes after I dosed flux rx i altered the air intake because it was overskimming, i will disconnect the scrubber and see if that changes anything. Thanks alot.