KH too high

[Reefer_Marc]

Hey guys

I am having a little problem with high KH.
I always had a bit of a problem with it but it wasnt too bad before.
I was just testing my water and my KH in the tank sits at 12.3
I also tested my RO/DI water, cant say the exact measurement because its so low, but it is below 2.5 dKH.
Also tested my new saltwater, it sits at around 6 dKH.
I know that KH is related to Mg and Ca, so i tested that as well. Mg is at 1400 and Ca at 425.
im just confused as to how it can get so high, if the fresh saltwater is at 6 dKH?

Im doing weekly waterchanges of 60 litres in my 400 litre tank.
Not many inhabitants currently, 4 chromis, 2 nemos and a tominis tang, few kenya trees, a leather coral, a clavularia and a BTA.

Anyone have any ideas on why it could go so high or what i can do to lower it?

Thanks in advance!
Reefer_Marc

 

[Garf]

Hey guys

I am having a little problem with high KH.
I always had a bit of a problem with it but it wasnt too bad before.
I was just testing my water and my KH in the tank sits at 12.3
I also tested my RO/DI water, cant say the exact measurement because its so low, but it is below 2.5 dKH.
Also tested my new saltwater, it sits at around 6 dKH.
I know that KH is related to Mg and Ca, so i tested that as well. Mg is at 1400 and Ca at 425.
im just confused as to how it can get so high, if the fresh saltwater is at 6 dKH?

Im doing weekly waterchanges of 60 litres in my 400 litre tank.
Not many inhabitants currently, 4 chromis, 2 nemos and a tominis tang, few kenya trees, a leather coral, a clavularia and a BTA.

Anyone have any ideas on why it could go so high or what i can do to lower it?

Thanks in advance!
Reefer_Marc

RODI should indicate zero on alkalinity tests. It's not unheard of for folks to read alkalinity tests from Salifert backwards. 6 Alk on new saltwater sounds a bit fishy.

 

[Reefer_Marc]

I have the Red Sea test kit, so as i understand the water will turn green once it reaches the correct value. But since its just a few drops its hard to see when the water actually turns green. So all i know is its below 2.5. According to my lfs here in our region its usually below 2, but up to 2 is normal.
Tested a month ago my new saltwater too, it was at around 6 as well. I use the pro reef sea salt from tropic marin, according to the label on the bucket it will have alk of 7 to 8 dKH. I have the salinity on the fresh saltwater a bit lower (around 1.022) currently because the salinity in my tank was a bit high. So i think the 6 dKH is not too far off, maybe its at 6.5, my eyes are not the best so its hard for me to see when the color changes from blue to green exactly

 

[Randy Holmes-Farley]

No dosing of anything?

Has nitrate been declining a lot (that boosts alk).

 

[Miami Reef]

If new saltwater at 35ppt should be 7-8dKH (let’s say 7.5dKH to round it) and your salinity is 1.022, the alk will be about 6.25dKH.

Makes sense that new saltwater is testing around 6dKH.

@Randy Holmes-Farley

 

[Reefer_Marc]

Only dosing Iodine, 1 ml a day. Plus once a week after waterchange microbe lift nite-out 2 and every 2 weeks the microbe lift special blend.
Nitrate has been declining, after my holiday on july nitrates were at 60, going back down to 6 now. Turns out my skimmer didnt want to work anymore, so had to replace it.

 

[Reefer_Marc]

If new saltwater at 35ppt should be 7-8dKH (let’s say 7.5dKH to round it) and your salinity is 1.022, the alk will be about 6.25dKH.

Makes sense that new saltwater is testing around 6dKH.

@Randy Holmes-Farley

Well that explains the testing of 6dKH.
So i guess the alk of the RO/DI cant be too bad if the fresh saltwater has a good reading, correct?

 

[Miami Reef]

Well that explains the testing of 6dKH.
So i guess the alk of the RO/DI cant be too bad if the fresh saltwater has a good reading, correct?

Correct.

You can also use the Red Sea kit in freshwater, but the alk should read 0 if the DI is relatively fresh.

 

[PharmrJohn]

What salt mix do you use? Some have an ALK of 12. Also, just to give you an idea, I used to keep my ALK between 15 and 18. That was my range. So, to me, 12 ain't terribly high......But this back in the Old Days, when an ALK reading of 15 wasn't regarded as incorrect.

 

[Reefer_Marc]

Correct.

You can also use the Red Sea kit in freshwater, but the alk should read 0 if the DI is relatively fresh.

How do you read an alk of 0 with the red sea kit? I wasnt able to see the colour with just the few drops, by the time i reached 2.5dKH all i could tell was that the colour is yellow, so overdose. So i know it must be below 2.5

 

[Reefer_Marc]

What salt mix do you use? Some have an ALK of 12. Also, just to give you an idea, I used to keep my ALK between 15 and 18. That was my range. So, to me, 12 ain't terribly high......But this back in the Old Days, when an ALK reading of 15 wasn't regarded as incorrect.

Im using the tropic marine pro reef sea salt, they say it has an alk of 7 to 8.
did you have any problems with that high alk?
Im having some trouble with algae, some macro algae and red slime, for quite some time already. Could that also be linked to the high alk?
I did icp‘s from time to time and always checked with my lfs, but we could never find the reason for the algae. All the parameters are good, except the alk which seems to be a bit high, at least from what i was told

 

[Miami Reef]

How do you read an alk of 0 with the red sea kit? I wasnt able to see the colour with just the few drops, by the time i reached 2.5dKH all i could tell was that the colour is yellow, so overdose. So i know it must be below 2.5

That means it’s 0.

 

[Garf]

Im using the tropic marine pro reef sea salt, they say it has an alk of 7 to 8.
did you have any problems with that high alk?
Im having some trouble with algae, some macro algae and red slime, for quite some time already. Could that also be linked to the high alk?
I did icp‘s from time to time and always checked with my lfs, but we could never find the reason for the algae. All the parameters are good, except the alk which seems to be a bit high, at least from what i was told

Are you adding a "PH" increaser to the tank?

 

[Reefer_Marc]

That means it’s 0.

Well thats perfect then!

 

[Reefer_Marc]

Are you adding a "PH" increaser to the tank?

Nope, no PH increaser. My PH is at 8.1, just checked this afternoon

 

[Randy Holmes-Farley]

Only dosing Iodine, 1 ml a day. Plus once a week after waterchange microbe lift nite-out 2 and every 2 weeks the microbe lift special blend.
Nitrate has been declining, after my holiday on july nitrates were at 60, going back down to 6 now. Turns out my skimmer didnt want to work anymore, so had to replace it.

If that nitrate was consumed instead of washed out by water change, it would add more than 2 dKH of alk.

 

[Reefer_Marc]

If that nitrate was consumed instead of washed out by water change, it would add more than 2 dKH of alk.

Could that affect it for a longer time? I did an ICP 2 months ago, nitrates were already down to 11.2 and the alk was at 9.9 then.
Could it take some time to hike the alk after the nitrates went down already?

 

[Randy Holmes-Farley]

Could that affect it for a longer time? I did an ICP 2 months ago, nitrates were already down to 11.2 and the alk was at 9.9 then.
Could it take some time to hike the alk after the nitrates went down already?

No, the effect is immediate.

 

[Reefer_Marc]

No, the effect is immediate.

Hmm, i guess its not the nitrates then.
Is there anything else that could hike the alk? It shouldnt just go up from 9.9 to 12.3 right? The water change i do the same every week, and the last times i checked the alk of the fresh water was around 6dKH

 

[Miami Reef]

Hmm, i guess its not the nitrates then.
Is there anything else that could hike the alk? It shouldnt just go up from 9.9 to 12.3 right? The water change i do the same every week, and the last times i checked the alk of the fresh water was around 6dKH

I wrote this short article that may be helpful:

The Ways Alkalinity can Accumulate in a Reef Tank

The Ways Alkalinity can Accumulate in a Reef Tank @Miami Reef "Why is my alkalinity rising?" is a seemingly simple question that consistently pops up in the chemistry section of Reef2Reef. However, it is a complex question since there are...

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