Dosing Kalkwasser Question

[Oshanickreef]

Hello everyone,
I wanted to see if anyone could help me out. I started dosing kalk a couple months ago and have been enjoying the results along with not having to refill my 2part containers every 3 weeks. I have an sps dominant reef with many colonies that have become a bit of a nuisance and require lots of trimming.
I start dosing kalk 2 hours before lights out because that’s when the lights start to dim and I notice my ph dropping. Then I don’t stop dosing until the lights come back on. Last night I ramped up my daily dose of kalk to 6300 ml per day from 5500ml per day. This morning my calcium and magnesium have dropped 20ppm and alk rose by .6 dkh overnight. Currently my Alkalinity is 9.4, calcium is 420, and mag is 1360. On a positive note, my ph since starting dosing has been very stable at 8.29 since last night.
My question is: why is my alk increasing while calcium is decreasing? I have since dosed 20 ml of my BRS calcium solution to bring it back up but my experience with dosing calcium and alkalinity unevenly is not great so I would like to avoid that when possible.

thanks in advance!
Nick

 

[Miami Reef]

The effect you are seeing is definitely not from the limewater (kalkwasser).

If anything, it tends to allow calcium to very slowly rise over time when maintaining alkalinity because it exactly matches the amount of calcium tot he amount of carbonate generated, but since magnesium and strontium get into precipitating calcium carbonate in place of some of the calcium, the actual demand is not precisely balanced, and calcium tends to slowly rise. I observed that in my tank over many years, and used a lower calcium mix (normal IO) for that reason.

In this case, it might be testing error, or water changes with a lower calcium mix. If you are actively using organic carbon dosing or growing macroalgae to reduce nitrate levels that are high, that can also raise alk and not calcium.

What salt mix are you using?

Calcium dropping much faster than alkalinity when using kalkwasser

So this is a weird question for you guys (particularly Randy). When I use kalkwasser my calcium drops much faster than my alk. For example I just checked and I'm reading 8 dKH and 370 ppm Ca after a week of using kalk in my topoff water. It was 8.4 dKH 430 ppm Ca at the beginning of the week...

www.reef2reef.com

 

[Oshanickreef]

Currently I am using instant ocean regular. My tester is the trident and last week I compared my alk, cal, and mag results from the trident with the Red Sea alk, cal, and mag test kits. To my surprise they were very similar. Can’t remember what cal and mag were but my alkalinity was +/- .05. I can try this again when I get home from work though.
I am pretty sure I’m not actively carbon dosing.. the things I’m actively dosing currently are: Neonitro @ 7ml per day, 2 part (Alk and Cal) @ 25-35 ml per day, kalkwasser @ 6300 ml per day, and tropic Marin trace elements A- and K+ @ 7ml per day.
Tested nitrate and phosphate a couple days ago. Nitrate = between 2.5 and 5. Phosphate = .09. I do have a 20 gallon fuge with a very small amount of chaeto in it that I have been slowly trying to eradicate. It’s sorta hard to access so I haven’t fully removed it all yet but soon I will be.

 

[Randy Holmes-Farley]

Declining nitrate will boost alk and not calcium, but nothing directly related to normal kalkwasser will.

 

[Oshanickreef]

Declining nitrate will boost alk and not calcium, but nothing directly related to normal kalkwasser will.

part of me was thinking that because a larger amount of Kalk was dosed that it increased ph and as a result my corals consumed more calcium... but this doesn't explain the alk increase.

I also think that maybe I should wait a few days before making any assumptions and let things balance. I used to try keep my Alk at 8 but now I am focusing on balancing ph instead of alk. I just worry that my alk will keep climbing. It is higher than it has been in years right now at 9.47 dkh. i have heard that 9+ alk will hurt sps when nutrients are low, which worries me.