Alkalinity- go stand in the corner

[BlueBayouReefHTX]

I've experienced some Alkalinity swings- my dosing has stayed fairly stable and no other livestock has been added to the tank recently, no expirations either. I've been trending higher alkalinity for awhile now, and over the last week i've been dialing back on my dosing (AFR 8mL/d). A few days ago, I tested my water and got a reading in the low 7s. I tested again and got the same result. I tested again the next day (Hanna) and were getting similar readings, decided to use my API and those results are in the same neighborhood (7s).
I confirmed both bottles of reagent were not expired. My cuvettes and syringes are all washed and rinsed in RODI after use to risk contamination.

Has everyone else experienced large swings in readings between new bottles of reagent? Could this cause such a variance? My recent numbers are attached.

 

[hoffmeyerz]

I haven't noticed any swings or changes between reagent bottles, and since I started dosing AFR my alk has stayed rock solid.
Have you experienced any rise in NO3, I know there is a correlation there as well.

 

[BlueBayouReefHTX]

I haven't noticed any swings or changes between reagent bottles, and since I started dosing AFR my alk has stayed rock solid.
Have you experienced any rise in NO3, I know there is a correlation there as well.

My nitrate averages 18-22 between any given week so no big changes there recently.

 

[hoffmeyerz]

Hmmmm. Did you have swings like this prior to starting afr?
Remember, it works best to get alk and cal levels where you want them first, then start dosing afr.

 

[BlueBayouReefHTX]

Hmmmm. Did you have swings like this prior to starting afr?
Remember, it works best to get alk and cal levels where you want them first, then start dosing afr.

I've been dosing AFR at the same amounts for maybe 6-8 months. I haven't noticed big jumps in my ALK like this. I find it curious it was right after I used a new bottle of reagent.

 

[Randy Holmes-Farley Verified Community Expert]

I expect it is a testing issue, not a real alk change.

 

[hoffmeyerz]

I've been dosing AFR at the same amounts for maybe 6-8 months. I haven't noticed big jumps in my ALK like this. I find it curious it was right after I used a new bottle of reagent.

That is interesting. I know there are people who have had issues with new reagents and a lot of people refrigerate the Hanna alk reagent to keep it stable. I haven't experienced any issues myself.

 

[exnisstech]

I've not experienced any big difference between reagents. I think the most I've seen between bottles is a 0.2 difference. As mentioned above I refrigerate mine. Also when a bottle is getting low I'll test it against a new bottle with the same water just to make sure there is not a big difference between the two. I've been using AFR for about a year now and I do have to tweak the dosage occasionally but normally only a few ml up or down. I target mid 8s dkh and currently dose 29ml a day with 65g total volume.

 

[BlueBayouReefHTX]

I've not experienced any big difference between reagents. I think the most I've seen between bottles is a 0.2 difference. As mentioned above I refrigerate mine. Also when a bottle is getting low I'll test it against a new bottle with the same water just to make sure there is not a big difference between the two. I've been using AFR for about a year now and I do have to tweak the dosage occasionally but normally only a few ml up or down. I target mid 8s dkh and currently dose 29ml a day with 65g total volume.

That's about the size of mine. Would you say your tank is stocked heavily or the opposite?

 

[exnisstech]

That's about the size of mine. Would you say your tank is stocked heavily or the opposite?

I would say medium. Only four fish but two are adult tangs the other two a damsel and six line. Coral wise far from packed but maybe medium as well.

 

[crazyfishmom]

I have 5 saltwater tanks, different volumes ranging from 24-250 gallons. I maintain alkalinity with AFR.

Alkalinity consumption in my experience can change dramatically based on the phosphate levels in my tanks. Have you tested phosphates in yours?

 

[BlueBayouReefHTX]

I would say medium. Only four fish but two are adult tangs the other two a damsel and six line. Coral wise far from packed but maybe medium as well.

Amazing tank! Mine is not nearly as full but it’s only a year old as well.

 

[BlueBayouReefHTX]

I have 5 saltwater tanks, different volumes ranging from 24-250 gallons. I maintain alkalinity with AFR.

Alkalinity consumption in my experience can change dramatically based on the phosphate levels in my tanks. Have you tested phosphates in yours?

Recent phosphate numbers- I would consider those stable but opinions may vary…

 

[exnisstech]

Amazing tank! Mine is not nearly as full but it’s only a year old as well.

Thanks. Mine really seemed to start coming together after the 1st year.

 

[rishma]

Recent phosphate numbers- I would consider those stable but opinions may vary…

Very stable.

 

[crazyfishmom]

Recent phosphate numbers- I would consider those stable but opinions may vary…

I agree. Very stable.

Do you use GFO to maintain those levels? Just want to make sure since GFO use can also mess with alkalinity.

 

[Cool Fish]

Whenever you test, try to do it at the same time everyday. Your Alk levels appear lower in the morning and higher in the evening. Lighting could be a factor.

 

[BlueBayouReefHTX]

I only use Carbon. I’ve decided to turn off my doser and just observe the daily changes since I’m still getting huge swings from day to day. I wonder if there is something wrong with the dosing pump or some kind of precipitate in my dosing container. I understood that once AFR is mixed up there shouldn’t be any issues.

 

[Randy Holmes-Farley Verified Community Expert]

I wonder if there is something wrong with the dosing pump or some kind of precipitate in my dosing container. I understood that once AFR is mixed up there shouldn’t be any issues.

Do you see a solid precipitate in it?