Need help- Alkalinity

[mwbeach]

Was gone for a week on vacation and came back to some corals not looking good. Did a group of tests.

Ammonia - 0
Nitrites - 0
Nitrates - 15
Phosphates 0.06
PH - 8.1
Salinity - 1.025
Alkalinity - 4.64

Obviously the alkalinity is the main issue here.

What should I do to get it back up? I started to dose Kalkwasser in my ATO a few weeks ago, could this be the cause?

 

[Randy Holmes-Farley Verified Community Expert]

4.6 dKH or 4.6 meq/l?

 

[mwbeach]

4.6 dKH or 4.6 meq/l?

Dkh

 

[mwbeach]

Just tested again and it’s at 4.86 dkh. 87 ppm on the Hanna Checker

 

[mwbeach]

Magnesium - 1600
Calcium - 464

 

[DHak]

That is very low, how much dkh were you typically dropping in a given time prior to dosing? Kalkwasser will increase Ca and alk evenly so you need to just increase alk about 1dkh per day using sodium bicarb or similar prior to relying fully on kalkwasser again

 

[mwbeach]

That is very low, how much dkh were you typically dropping in a given time prior to dosing? Kalkwasser will increase Ca and alk evenly so you need to just increase alk about 1dkh per day using sodium bicarb or similar prior to relying fully on kalkwasser again

Agreed. Not sure on how much it was dropping. I have the Red Sea 3 part Reef Foundations. Going to start using that and getting things in line. I’m doing a 30% water change today, then will test tonight and begin using the Red Sea Foundations to get back in line.

 

[Dkeller_nc]

Was gone for a week on vacation and came back to some corals not looking good. Did a group of tests.

Ammonia - 0
Nitrites - 0
Nitrates - 15
Phosphates 0.06
PH - 8.1
Salinity - 1.025
Alkalinity - 4.64

Obviously the alkalinity is the main issue here.

What should I do to get it back up? I started to dose Kalkwasser in my ATO a few weeks ago, could this be the cause?

You noted that you're using kalkwasser in the ATO; does this mean that you're mixing it up in a separate bucket, letting it settle, then pouring the clear liquid into the ATO? Or are you adding the kalk powder directly to the ATO, elevating the pump so that it doesn't put the slurry into the tank?

If it's the latter, how often do you replace the kalk powder? I ask because when freshly mixed, the undissolved slurry at the bottom of the container is all calcium hydroxide (kalk powder). Over time, however, calcium carbonate forms in the solution from the reaction of calcium hydroxide and atmospheric carbon dioxide, and settles out on the bottom of the container. If the aquarist simply continues to add RODI to the container, the material at the bottom will be almost all insoluble calcium carbonate, and there will be almost no calcium hydroxide dissolved in the clear liquid.

 

[Saltyreef]

You should do consumption log on your cal and alk over 5 days then average it out.
This will let you know,

A. Your reccomended water change frequency if relying on water changes as macro element replacement.

B. Your proper kalk saturation needed for the ATO(usually full saturation if stocked moderately)

C. If you need to start 2 part dosing to keep up with demand too.

I have a somewhat lightly stocked 40 gallon tank with mainly lps.
I do a 10% w/c weekly to cutdown on macro element swings. (only relying on water changes at the moment)
Have fully saturated kalk in the ATO and now am needing to start 2 part dosing as even with the kalk and weekly water changes with RSCP (high alk) my demand is more than i can realistically keep up with.

Try it out and let us know how it goes....
As for now yes do a large 30% water change and retest after a few hours.
Honestly that low of alk is more stressful on the corals than bringing it to 6-7dkh rapidly with a water change so go for it!
My stuff melts below 7dkh in my tank.

 

[mwbeach]

Just mixed up 10 gallons of fresh saltwater. The Alk is testing at 10.56. Going to be doing the water change shortly once it gets to temp.

 

[Saltyreef]

That should do the trick and get you up above 7 hopefully. Good luck man!

 

[Randy Holmes-Farley Verified Community Expert]

As folks have mentioned, if the ato water wasn’t saturated with calcium hydroxide, adding more or mixing it differently may help.

 

[mwbeach]

Thanks all for your help


I did the 30% water change and just tested it. ALK is now at 7.43 dkh. Going to add some Alk tomorrow to get it over 8.5. After that, I’m going to stop all dosing and measure the decline over a few days and then narrow in specific dosing to get it balanced.

 

[Dkeller_nc]

I don't know what's in your tank, but I think most of us would recommend that you go -slowly- when it comes to correcting your alkalinity value. Personally, I'd probably go with 10% daily water changes for a week, and monitoring the alkalinity every day to ensure that it doesn't go up by more than 0.5 dKH every 24 hours. SPS are especially sensitive to alkalinity swings, and a sharp rise is probably more damaging than a gradual drop.

One other thing to check is to make sure that your specific gravity is actually correct. It's possible to get an alk of 4.5 dKH if there are a lot of corals/coralline algae consuming carbonate, but a contributing factor might well be a specific gravity that's significantly lower than your testing instrument would suggest.

 

[Saltyreef]

I whole heartedly agree with the above comments. Now that its at 7.3...leave it be for a few days and let everything adjust and acclaimate. Dont add anymore alk right now. It would be a good time to test daily and find your 5 day average before you add any more. And now try not to raise more than suggested above. .5dkh per day