need help on kalk

[vashawn]

i have a 265 mixed reef about 20% stock with 5 sps and mostly softies and lps.
I have been dosing with esv cal, alk and mag
cal:455
alk:8 dkh
mag:1200
nit, amm, phos close to zero or very low

question should i stop dosing w/cal, alk, and mag and start dosing with kalk?
i dont have any problem with my tank but others told me i should use kalk instead.
why

[dkeller_nc]

I think most everyone on the chemistry forum would tell you that if you don't have any problems with your tank, don't make changes. Period. No matter how many well-meaning folks tell you otherwise.

There are three potential upsides to kalk dosing: it's an "automatically balanced" supplement with respect to Calcium and Alkalinity. It's pH is high, and it can provide a temporary pH boost to a tank where the pH is stubbornly low. Potentially, it can precipitate some phosphate in the water as calcium phosphate.

However, kalk is quite dilute in terms of calcium and alkalinity. Most find that kalkwasser alone in a well-stocked tank cannot keep up with calcium and alkalinity consumption. It also generally needs to be dosed with a dosing pump in a tank that needs alkalinity stability, such as an SPS tank. So that's an extra piece of equipment to buy and set-up if you don't already have an appropriate device for the purpose. You can, depending on where and how the kalk is dosed, also run into calcium carbonate precipitation issues, particularly inside return pumps in a sump.

[bertoni]

I agree with these comments. Kalk has one extra property: it does not affect the salinity over the long term. The ESV supplement will raise the SG gradually, so a bit of dilution often is needed. That's a minor difference, though. Personally, I'd leave well enough alone.