DkH seemingly dropped very fast

[csd99]

Hello all, yesterday I took a couple alkalinity readings on my tank and noticed that it has seemingly dropped 2 dkh in 24 hours (from 9.3 to 7.0). I’m wondering if the consensus is that I was just testing poorly before or if there is something I did that could skew results? Of note: I added about a gallon of RODI water to drop salinity by .001 about an hour or so before I took the test that read 7.0. I have since tested again this morning to find that the Alk is still at 7. All my corals look happy, including a torch and a few montis & stylophora.

 

[KrisReef]

Probably testing error, or corruption of the test solution during the process?

What test kit(s)?
How big of a tank? ( I can't do the math for RODI dilution ;) )
What is the usual level and how do you add AlK?

 

[csd99]

Probably testing error, or corruption of the test solution during the process?

What test kit(s)?
How big of a tank? ( I can't do the math for RODI dilution ;) )
What is the usual level and how do you add AlK?

I use the red sea test kit. Water volume is roughly 45 gallons after all the rock and equipment was added. I think I’ve come to the conclusion that it was a testing error as I use tropic Marin pro reef salt. 7.0 is pretty on track for what I would expect it to be after some consumption

 

[Randy Holmes-Farley Verified Community Expert]

Can you show a picture of the tank? Coralline alone (in a soft coral tank) can use 2 dKH per day.

 

[csd99]

Can you show a picture of the tank? Coralline alone (in a soft coral tank) can use 2 dKH per day.

The lights are all off right now but I can say that about 1/3 of the rock in my display is covered in coralline. I also have 4 sps frags and 2 lps. I tested throughout the day today and it remained constant. Will check again tomorrow

 

[lmfbs]

Hey sorry to bump this thread but I'm having a very similar issue in my tank. Using over 1.5 dkh per 24hr period, 130g system. I don't have a whole lot of pink coralline yet, but it's growing fast. I'm guessing the usage is coralline growth despite the lack of coverage?

 

[SGV - Bluestar]

Take your water to your LFS to see if they can test it, or call them first to see which can do testing for you. Might have a bad test kit, but if it's really that low then slowly add Alk or just do a water change instead. Alk consumption is usually Coraline or algae, but your cal should also goes lower if it's coraline.

 

[Randy Holmes-Farley Verified Community Expert]

Hey sorry to bump this thread but I'm having a very similar issue in my tank. Using over 1.5 dkh per 24hr period, 130g system. I don't have a whole lot of pink coralline yet, but it's growing fast. I'm guessing the usage is coralline growth despite the lack of coverage?

That certainly could be it.

 

[lmfbs]

Take your water to your LFS to see if they can test it, or call them first to see which can do testing for you. Might have a bad test kit, but if it's really that low then slowly add Alk or just do a water change instead. Alk consumption is usually Coraline or algae, but your cal should also goes lower if it's coraline.

Calc has been decreasing too, so that makes sense. I've tested it with 2 different test kits so I'm reasonably sure of the result. The closest fish shop to me is over 400km away (if that sounds ridiculous, it's because it is)

 

[Reefdiculous22]

Can you show a picture of the tank? Coralline alone (in a soft coral tank) can use 2 dKH per day.

I’m glad I saw this. I tested my alk today before water change and it was at 5.3. Usually it is 8.2-8.9. I was wondering what would have caused such a drop in the course of a week, but I have noticed quite a bit of new coralline growth.
Didn’t mean to bump the thread , but I was looking around trying to find some answers before starting a new thread.

 

[Reefdiculous22]

Calc has been decreasing too, so that makes sense. I've tested it with 2 different test kits so I'm reasonably sure of the result. The closest fish shop to me is over 400km away (if that sounds ridiculous, it's because it is)

Can you show a picture of the tank? Coralline alone (in a soft coral tank) can use 2 dKH per day.

Calc has been decreasing too, so that makes sense. I've tested it with 2 different test kits so I'm reasonably sure of the result. The closest fish shop to me is over 400km away (if that sounds ridiculous, it's because it is)

I fell your pain. I have to drive an hour and 45 min to my lfs.
How much did your calc drop. Mine only dropped about 29ppm in the course of a week. It was 407 when I checked today. Can’t see why my alk would have dropped so much in the same week if my calc was still over 400

 

[Randy Holmes-Farley Verified Community Expert]

I fell your pain. I have to drive an hour and 45 min to my lfs.
How much did your calc drop. Mine only dropped about 29ppm in the course of a week. It was 407 when I checked today. Can’t see why my alk would have dropped so much in the same week if my calc was still over 400

Test error, or accumulating nitrate which will deplete alk and not calcium.

 

[lmfbs]

I fell your pain. I have to drive an hour and 45 min to my lfs.
How much did your calc drop. Mine only dropped about 29ppm in the course of a week. It was 407 when I checked today. Can’t see why my alk would have dropped so much in the same week if my calc was still over 400

My calc was dropping only a wee bit, but definitely being consumed.

Your situation seems almost definitely testing error, especially if your calc is only 29 less?

 

[Reefdiculous22]

Test error, or accumulating nitrate which will deplete alk and not calcium.

That may be. My nitrate was 27ppm and phos was .22

Test error, or accumulating nitrate which will deplete alk and not calcium.

 

[Reefdiculous22]

My calc was dropping only a wee bit, but definitely being consumed.

Your situation seems almost definitely testing error, especially if your calc is only 29 less?

My calc was dropping only a wee bit, but definitely being consumed.

Your situation seems almost definitely testing error, especially if your calc is only 29 less?

I’m not sure. I was using Red Sea pro kit. I usually use Hannah checker. I tested twice and came back with the same result. I will say that the reiteration solution was very weak in color. Usually the start and end colors are darker and it was really really light. There may be something wrong the reagent I have.

 

[Reefdiculous22]

I’m not sure. I was using Red Sea pro kit. I usually use Hannah checker. I tested twice and came back with the same result. I will say that the reiteration solution was very weak in color. Usually the start and end colors are darker and it was really really light. There may be something wrong the reagent I have.

Tritration solution*