Alkalinity puzzle - please help

[Butuz]

Guys, it is my understanding that Kalkwasser does not raise alk, just maintains it. Apprx 2 weeks ago, my alk was stable at 8.3, I added Red Sea a few times over few days to get it to 8.7. Did not add any more over the past week. Recently started Seachem Kalk to my ATO RODI water (even lower dosage than they recommend, been doing 15 teaspoons per 10g). However, 5 days ago, my alk went to 9.3, then 9.5 and its now at 9.7. I have not dosed alk since I got it up to 8.7. Should I be worried? What may be causing this? I added a bunch of frags from topshelf, rasta hammer, mix of sps, zoas, etc. they all seem to be doig well. Should I be worried, or should I maintain the same Kalk level and let the system settle at a certain alk level? PH is at 8.2-8.3 stable, salinity 1.026, calcium 450, magnesium 1,370.

Many thanks guys. I am expecting a rose bubbletip anemone from topshelf this friday, so want to create perfect conditions prior to its arrival.

 

[Larry L]

Adding Kalkwasser definitely increases both calcium and alkalinity, so if you are dosing more than is needed to make up for what's being used by your corals, the levels of one or both will increase. Kalkwasser is calcium hydroxide (lime), and the CO2 in your water will react with the hydroxide ions, allowing the calcium to go free and converting the hydroxide part into bicarbonate, which is what increases alkalinity.

 

[Butuz]

Adding Kalkwasser definitely increases both calcium and alkalinity, so if you are dosing more than is needed to make up for what's being used by your corals, the levels of one or both will increase. Kalkwasser is calcium hydroxide (lime), and the CO2 in your water will react with the hydroxide ions, allowing the calcium to go free and converting the hydroxide part into bicarbonate, which is what increases alkalinity.

THANK YOU, that explains. My tank is still in its infancy and nothing mature enough to consume. I recall reading somewhere that Kalk only maintains alk, does not raise it, hence the confusion. I know what to do now. Will lower Kalk to keep alk at 9 and will increase from there, if consumption drops it. Thank you.

 

[Larry L]

Will lower Kalk to keep alk at 9 and will increase from there, if consumption drops it. Thank you.

You're welcome. Using Kalk can be tricky because most people add it to their topoff water, so the rate it gets dosed depends only on the rate of evaporation, which a) can vary depending on temp and time of year, and b) is not related at all to how fast or slow your tank is consuming calcium and alkalinity.

 

[ScottF83]

I read this article last night. Explains in detail how and why Kalkwasser does this:

https://www.advancedaquarist.com/2003/2/chemistry

 

[Jdavison911]

https://www.reef2reef.com/blog/the-many-methods-for-supplementing-calcium-and-alkalinity

I simply adjust how much Kalk I mix in with my top off water. Per Randy the max is about 2 teaspoons per gallon of fresh water, anything above that doesn't do anything additional. If your seeing a small increase back off on your mixture a little, instead of adding 1 teaspoon per gallon add 1/2 teaspoon per gallon. I love the stuff and buy every bag at Walmart when they have it. I top off about 5 gallons a day and this is a great substitute for adding Alk and Cal to the tank. I mix about 1/2 cup to 15 gallons and this seems to work for me.

 

[Butuz]

https://www.reef2reef.com/blog/the-many-methods-for-supplementing-calcium-and-alkalinity

I simply adjust how much Kalk I mix in with my top off water. Per Randy the max is about 2 teaspoons per gallon of fresh water, anything above that doesn't do anything additional. If your seeing a small increase back off on your mixture a little, instead of adding 1 teaspoon per gallon add 1/2 teaspoon per gallon. I love the stuff and buy every bag at Walmart when they have it. I top off about 5 gallons a day and this is a great substitute for adding Alk and Cal to the tank. I mix about 1/2 cup to 15 gallons and this seems to work for me.

Thanks! You must have a huge tank if losing that much water to evaporation daily! I was thinking the same thing, currently I do 15 teaspoons for 10g, will reduce to 10 and see if it stabilizes. Agree, adding kalk to ATO seems easy to me, once dialed in. As precise as dosing. I can then use my 4 dosing chambers for something else.

 

[Jdavison911]

I have almost 500 gallons in my new system. If Im running the dehumidifier I evap 4-5 gallons, if its off then around 3-4 gallons a day. Its a very cheap method of adding needed stuff to the tank. Ive ran it on every tank I have owned and will continue to do so. Good luck and shouldn't take much time to get dialed in. Once you start adding corals that use up alk and ca you will need to make adjustments up to the full 2 teaspoons per gallon. At some point if you continue to add stuff you will need to dose or go over to a ca reactor.