150 gallon SPS with only Kalk?

rocknut · Mar 30, 2016

So, I am in the beginning stages of a reef "re-boot" on my 150 gallon reef (long story for another time), but after making a big mess with various carbon dosing schemes, I am trying to go back to the way I ran my first reef years ago: skimmer, rock/sand, macro algae, T5 lights, good flow.

I am having a hard time making a decision on alk/calcium supplementation, however. The tank will be primarily SPS, but I have never been one to cram the tank full of corals, and am planning to just have fewer amounts of corals that will *hopefully* grow into larger colonies. I have an Apex DOS dosing unit that I can use for two part, as I have done in the past, but am intrigued with the idea of running a kalk reactor instead. I haven't run kalk before because it always seemed like too big a variable since the amount of alk/calcium going into the tank would vary depending on the amount of water being topped off, which would in turn vary depending on how much evaporation the tank was producing at any given time - just seemed like the alk level in particular would be hard to keep stable.

So, I had the idea of running my doser into the reactor (pulling water from my RO top off reservoir) that way I could add a controlled amount of kalk each day (start at 1,000 ml / day) and adjust up or down to keep alk levels stable. The ATO would still remain hooked up to add the remaining top off for the day of pure RO water. With this being said, does this make any sense knowing that I have a dosing pump already on-hand that can just dose 2 part with no trouble? I understand that down the road the kalk reactor may not be able to keep up with demand, so could always begin adding 2 part then to make up the difference, but would love to get some opinions on this. Is there an advantage of trying to use kalk instead of just adding 2 part, or am I just making things unnecessarily complicated? Guess I am just in the middle of going down the rabbit hole of older techniques, and thought that a kalk reactor deserved another look.

CodyRVA · Mar 30, 2016

I think you're going down the rabbit hole, but I always take the practical & simplistic approach. I would dose ALK/CA now, why wait. IMO tune in your dosing now, get it on point, that way you can always increase the ML per day as your corals grow or as you add more colonies. Weekly testing will indicate when you need to increase or decrease your doses. There will be less shock to the system, the system would remain much more stable when the time comes for an adjustment and all you had to do was up the dose of ML vs switching from KALK to 2 part, but to each their own.

rocknut · Mar 30, 2016

CodyRVA said:
I think you're going down the rabbit hole, but I always take the practical & simplistic approach. I would dose ALK/CA now, why wait. IMO tune in your dosing now, get it on point, that way you can always increase the ML per day as your corals grow or as you add more colonies. Weekly testing will indicate when you need to increase or decrease your doses. There will be less shock to the system, the system would remain much more stable when the time comes for an adjustment and all you had to do was up the dose of ML vs switching from KALK to 2 part, but to each their own.

That is exactly the sort of feedback I was looking for. Appreciate you taking the time to read and respond.

Drauka99 · Mar 30, 2016

Agree, you have the equipment and the know how to use 2 part. I say go with it. my tank just doesn't evaporate enough for me to reliably supplement with kalk water.

rocknut · Mar 30, 2016

Drauka99 said:
Agree, you have the equipment and the know how to use 2 part. I say go with it. my tank just doesn't evaporate enough for me to reliably supplement with kalk water.

Thanks for reading and responding. Think I am in agreement, and will just stick with dosing two part. Thanks again!

Randy Holmes-Farley · Mar 31, 2016

Generally, an SPS heavy tank cannot be maintained by limewater alone, although mixed reef tanks often can.

FWIW, I compare the pros and cons of different methods here:

The Many Methods for Supplementing Calcium and Alkalinity - REEFEDITION
https://www.reef2reef.com/blog/the-many-methods-for-supplementing-calcium-and-alkalinity

Myka · Mar 31, 2016

I use kalk plus 2-part on my tank. I have a 3 head doser and it runs calcium, alkalinity, and kalk. I manually add a bit of extra magnesium to my waterchange saltwater. I have a 3-gallon pail of saturated kalk which doses 800 mL per day split into 20 doses (there is a no-dose gap during peak lighting) which is perfect for a once every 2 weeks refill. When the demands of the tank grew beyond the 800 mL per day the kalk was providing I started adding 2-part (Fauna Marin Balling Lite actually). I have an ATO that tops up RO/DI when needed. I like the (limited) benefits of using kalk, so I keep it up. In the past I've also added vinegar to the kalk mixture for some very mild carbon dosing (and more concentrated kalk) with great results, but my tank doesn't need it these days. My new tank is still pretty young, but I did this method for several years on my last SPS tank too.

All that said, I'm in the midst of switching to the Aquaforest Probiotic method and will be using their Component 1+ 2+ 3+ for dosing demands in lieu of the cal, alk, and kalk. I like the idea of three premixed containers for simplicity. I guess after 20 years of dosing I'm getting lazy.