Doser off, Alk still rising

[Shadowspop]

Confused... My alk is rising daily. Currently sitting at 8.74, so it's not concerning me. The confusing part is that I have my doser turned off for 3 days. Cal is rising slowly, but I'm only dosing .2 ml/day. Mag is rising very, very slowly, even though I'm dosing 28ml/day. What could be causing these odd changes and my alk increasing. Corals are doing great. Tank is thriving.

I ran a manual test and all of the numbers were pretty close to the Triton, and reflecting a similar trend.

8.42 on 4/29
8.70 on 4/30
8.74 on 5/1

Doser off


RS xxl 900- 240 gal total
Salinity 1.025
Nitrate 20

 

[Bo.]

Do you use kalkwasser? How are you doing calcium? There's relationship between carbonate hardness depending on tests whether you are dosing alk or not. And calcium and mag can both still raise it a tiny bit...

Give this a read through and see if it helps.

What is Alkalinity?

Most reefkeepers know they need to measure alkalinity, and most know it has something to do with carbonate. But what is alkalinity exactly? Why is it important? How is it measured? This article will answer those questions and give you all of the...

www.reef2reef.com

 

[blasterman]

At a minimum I would get a second opinion/test on alk from another source.

 

[arking_mark]

What has you pH measured over this time?

 

[Staghorn]

Is your refractometer properly calibrated? Are you keeping up with top off water?

 

[theocorals537]

Is your salinity measurement accurate? Salinity changes alk rapidly

 

[Shadowspop]

Do you use kalkwasser? How are you doing calcium? There's relationship between carbonate hardness depending on tests whether you are dosing alk or not. And calcium and mag can both still raise it a tiny bit...

Give this a read through and see if it helps.

What is Alkalinity?

Most reefkeepers know they need to measure alkalinity, and most know it has something to do with carbonate. But what is alkalinity exactly? Why is it important? How is it measured? This article will answer those questions and give you all of the...

www.reef2reef.com

My calculations is OK, but I'm still not dosing what I think I should be I'm only dosing .2 ml/day in 240 gal. I know my mag is low and I've been trying to raise that. Dosing 30ml of mag/day and barely moving the needle. I just don't understand how the Alk is still rising. It was at 7.55 on April 6. Obviously too low, but it was steadily in the rise...and here we are. The funny part is that my corals are doing awesome. Having lots of growth and everything looks great. Not dosing anything other than Alk, Cal, and Mag. Feeding the corals a couple of times a week with Fuel and Benepets.

Is your salinity measurement accurate? Salinity changes alk rapidly

Yup, I checked the calibration first thing. It did drop a bit today, we'll see what happens throughout the day.

 

[Bleigh]

Is there a possibility that you had some alk precipitate out? As the calcium and magnesium are raising, there’s a chance that precipitate is dissolving.

 

[jassermd]

If you’re using a Trident for testing, you may want to check your sample and reagent lines. I ran into a similar issue and it turned out the reagent line had a micro bubble.
I’d check the sample line and re-prime it. If your reagents are close to being done, you may want to change them out an recalibrate. If not, at least re-prime all 3.
Or confirm your readings with a Hanna checker. I racked my brain over the same issue for days until I figured out it was the Trident reagent line.
Just my 2 cents...

 

[Deep]

8.70 to 8.74 is probably just imprecise testing results. I wouldnt worry about rising alkalinity until this climbs over 9 for example.
Also are these results from exactly same time of the day on both days?

 

[Shadowspop]

Is there a possibility that you had some alk precipitate out? As the calcium and magnesium are raising, there’s a chance that precipitate is dissolving.

Possibly, but not sure from where. 250# of CaribSea rock, live sand, about 5# of matrix rock in my sump. Haven't really added anything to the tank other than frags.

 

[arking_mark]

What has you pH measured over this time?

You Alk consumption will most likely track to pH. Higher pH = higher consumption; Lower pH = less consumption.

Check to see if you had a pH dip during that time.

 

[Uncle99]

When MG is low, Alk and CA will not read correctly.
Get MG up first to 1350-1400ppm and retest.

 

[Randy Holmes-Farley]

When MG is low, Alk and CA will not read correctly.
Get MG up first to 1350-1400ppm and retest.

That is not correct. Alk and calcium "read" correctly, regardless of magnesium levels.

 

[Randy Holmes-Farley]

My calculations is OK, but I'm still not dosing what I think I should be I'm only dosing .2 ml/day in 240 gal. I know my mag is low and I've been trying to raise that. Dosing 30ml of mag/day and barely moving the needle. I just don't understand how the Alk is still rising. It was at 7.55 on April 6. Obviously too low, but it was steadily in the rise...and here we are. The funny part is that my corals are doing awesome. Having lots of growth and everything looks great. Not dosing anything other than Alk, Cal, and Mag. Feeding the corals a couple of times a week with Fuel and Benepets.
Yup, I checked the calibration first thing. It did drop a bit today, we'll see what happens throughout the day.

I think that must be a typo?

You are dosing 0.2 mL of something (what???) to a 240 gallon tank? Like with a tiny syringe? A single drop?

 

[Shadowspop]

8.70 to 8.74 is probably just imprecise testing results. I wouldnt worry about rising alkalinity until this climbs over 9 for example.
Also are these results from exactly same time of the day on both days?

I believe those times were both at noon. I've been doing my manual testing at noon as well.