Rising Alk

mdbronco

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Hi,

Over the past month, my alk keeps climbing steadily. I test the same time each week, and everything remains in line except the alk lately. Same salt since starting the tank over a year ago (RS Coral Pro). I change water the same time each week (10%). All rock has been in the tank for at least 6 months (last random pieces added then). Same test kit as always.

Calcium 410
Mag 1320
Phos 0.25
Nitrate - 0
Nitrite - 0
Ammonia - 0
PH 8.2
Alk - used to be 8 four weeks ago, now is 16
Sal -1.026

I have always dosed kalk in my ATO but I guess I should stop? Why is this creeping up? How do I remedy safely without disrupting everything else?

Mixed reef, with SPS, LPS, and softies. Macro algae as well. What ill effects can be expected with this high of number?

Thanks!
 

Hemmdog

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Your coral has stopped consuming, most likely your phos being sky high with zero nitrates. Stop dosing kalk and get your phos down and feed your fish more good frozen food to get nitrate up.
 

Randy Holmes-Farley

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I have always dosed kalk in my ATO but I guess I should stop? Why is this creeping up? How do I remedy safely without disrupting everything else?
!
Because you are dosing too much. Use less.
 

Brett S

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Alk - used to be 8 four weeks ago, now is 16
I wonder if there is a testing error. Either a bad test kit or a mistake made during testing. If your alkalinity really rose from 8 to 16dkh over 4 weeks then most of your corals would be dead. That is a huge jump over a reasonably short time period and 16 is well outside the safe range.

The first thing I would do is get another test kit to verify that your alkalinity is really at 16dkh. If so then you need to bring it down, but you still want to bring it down reasonably slowly or you’ll just further shock anything that is still living. I might try to do a few water changes over a period of a few days to get it back down to a more reasonable number like 11 or 12dkh, but don’t drop it by more than 1dkh per day. Once it’s there then I would slow down even more and take a few weeks to get it back down to 8 or 9.

But before you do anything too drastic get another test kit to verify that you really are at 16dkh
 
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mdbronco

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I wonder if there is a testing error. Either a bad test kit or a mistake made during testing. If your alkalinity really rose from 8 to 16dkh over 4 weeks then most of your corals would be dead. That is a huge jump over a reasonably short time period and 16 is well outside the safe range.

The first thing I would do is get another test kit to verify that your alkalinity is really at 16dkh. If so then you need to bring it down, but you still want to bring it down reasonably slowly or you’ll just further shock anything that is still living. I might try to do a few water changes over a period of a few days to get it back down to a more reasonable number like 11 or 12dkh, but don’t drop it by more than 1dkh per day. Once it’s there then I would slow down even more and take a few weeks to get it back down to 8 or 9.

But before you do anything too drastic get another test kit to verify that you really are at 16dkh
Thanks for this. I ended up buying a different brand of test kit and it was verified. But I stopped dosing kalk in my ATO and just tested it again after 2 days. It has come down from 16 to 13. Things seem to be fine, in fact my softies seem happier than they have lately.

My ignorance with kalk was that although of course you can always dose too much, I figured that once the saturation point was reached, it didn't really "matter" too much about putting an extra teaspoon or two into the mixture. Apparently this was wrong...
 
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mdbronco

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If using kalk in your ATO, it's possible you may have more evaporation than usual and therefore dosing more than usual without you knowing. I agree to stop dosing for now, monitor, and continue dosing at a reduced rate once levels come back down.
Yes this makes a lot of sense actually.
 
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mdbronco

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That and also your salt is higher in alk too. Are you matching the alk of the salt to your display tank alk?
Sorry I don’t quite understand. I match the salinity obviously when doing water changes, but how would I go about matching the alk? RS Coral Pro has an alk of 11.5. Are you saying then that I shouldn’t use it if I’m shooting for a stable alk of 9-10?
 

SeaDweller

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Sorry I don’t quite understand. I match the salinity obviously when doing water changes, but how would I go about matching the alk? RS Coral Pro has an alk of 11.5. Are you saying then that I shouldn’t use it if I’m shooting for a stable alk of 9-10?
There are ways to bring down the alk of the mixed water before you add it to your display. If your display is 8.0 and you always add higher alk water change water each week, then it will increase your alk.

You can use Seachem acid buffer or muriatic acid to reduce your alk in the water change water before you add it to your tank.
 
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mdbronco

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There are ways to bring down the alk of the mixed water before you add it to your display. If your display is 8.0 and you always add higher alk water change water each week, then it will increase your alk.

You can use Seachem acid buffer or muriatic acid to reduce your alk in the water change water before you add it to your tank.
Ok thanks. TBH this might start to get a bit over my comfort level, even though it sounds pretty straight forward. I used to own a pool company and am very familiar with muriatic acid and dosing etc, but hopefully I can get it back to the range it once was before going that route. Thanks for the tips!
 
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mdbronco

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Your coral has stopped consuming, most likely your phos being sky high with zero nitrates. Stop dosing kalk and get your phos down and feed your fish more good frozen food to get nitrate up.
Hi again - a question on how long alk should take to come down after getting phos down? I've been able to get my phos to read between 0 and 0.03 for about a week after adding GFO via a reactor, but my two alk test kits still have it sitting stubbornly between 14 - 16....

Nitrates are still zero but I have been trying to get up a bit more with different feeding tactics. I've had some issues with overall balance (posted on another thread) and I think my bio-filter has been knocked off course somewhat.

Some acros have begun to STN (birdsnest), while others don't seem affected yet but aren't growing. Softies are "fine" as are LPS. By "fine" I mean not retracting but def not thriving. Just maintaining.

As you and the Master RHF said - I have stopped dosing kalk about a month ago.
 

Brett S

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The huge quick rise in alkalinity likely shocked the corals and they may take some time to recover. As you said, your SPS doesn’t seem to be doing well. If it’s not growing then it’s not using calcium and alkalinity and the levels won’t go down. 14 to 16 is still very high, even borderline dangerously high and you may be better served by slowly lowering the level with water changes using a salt mix that is low in alkalinity.

Of course, the keyword here is slowly. I would probably try to get it down to the 11-12 range, which is still high, but well within the safe range. I would take at least a week or two doing several water changes each week to get it down into this range.

It’s difficult to say how quickly the corals will recover, but until they do and start growing again you won’t see alkalinity start being consumed naturally.
 
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Randy Holmes-Farley

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Hi again - a question on how long alk should take to come down after getting phos down? I've been able to get my phos to read between 0 and 0.03 for about a week after adding GFO via a reactor, but my two alk test kits still have it sitting stubbornly between 14 - 16....

Nitrates are still zero but I have been trying to get up a bit more with different feeding tactics. I've had some issues with overall balance (posted on another thread) and I think my bio-filter has been knocked off course somewhat.

Some acros have begun to STN (birdsnest), while others don't seem affected yet but aren't growing. Softies are "fine" as are LPS. By "fine" I mean not retracting but def not thriving. Just maintaining.

As you and the Master RHF said - I have stopped dosing kalk about a month ago.
I’m not sure it will be strongly impacted by lowering phosphate, but most folks see alk drops of 0.3 to 3 dKH per day.
 

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