KALK + A4R

Kika · 2026-09-25T11:27:25-0400

Hey folks,

Anyone here doing kalk + all for reef? If so how you do this? A4R during lights On and Kalk when lights are off? Also can you share some ph historical data while dosing these products?

Thanks in advance

hondacbr600rr · 2026-09-25T11:28:24-0400

I’ve been looking to add Kalk to my AFR routine and also hope to learn the best way to do so.

Are you looking to get the PH benefits from the Kalk?

Kika · 2026-09-25T11:34:25-0400

hondacbr600rr said:
I’ve been looking to add Kalk to my AFR routine and also hope to learn the best way to do so.

Are you looking to get the PH benefits from the Kalk?

Correct, I’m looking to improve ph by adding some hydroxide to my dosing schedule. At the same time I want to still have the benefit from adding traces while using A4R, but I’m open to other suggestions.

Ps: I’ll be doing monthly icps to supply whatever is missing or need corrections from A4R

exnisstech · 2026-09-25T11:42:04-0400

Do you run a skimmer? My daily pH was 7.6-7.9 daily. I added a skimmer with an outside airline and now pH is 8.0-8.3 sometimes hitting 8.4. From reading people that dose both they dose kalk at night when pH drops.
TBH my acros did very well at the lower pH. The only benefit I've seen from increasing pH is faster growth of stoney coral, nothing else. If you don't need accelerated growth it may not be worth the trouble.

Kika · 2026-09-25T12:05:36-0400

exnisstech said:
Do you run a skimmer? My daily pH was 7.6-7.9 daily. I added a skimmer with an outside airline and now pH is 8.0-8.3 sometimes hitting 8.4. From reading people that dose both they dose kalk at night when pH drops.
TBH my acros did very well at the lower pH. The only benefit I've seen from increasing pH is faster growth of stoney coral, nothing else. If you don't need accelerated growth it may not be worth the trouble.

This is great data reference! I do run a skimmer, and yes, my goal is to get my sps grow improved. I will work on an outside line from the skimmer as a test and go from there.

exnisstech · 2026-09-25T12:14:18-0400

It definitely increased growth in my tank. I no longer had to look at before and after pics to see growth. After two months I had increased my AFR from 35ml daily to 60ml. I'll link a very good article on pH and toward the bottom of the article it tells how to perform an aeration test to determine if lower pH is being caused by elevated indoor CO2 or something else. The outside airline will only help if elevated indoor CO2 is the cause but it's the most common cause I believe.

https://www.reef2reef.com/ams/understanding-ph-in-reef-tanks-part-one.1133/

Kika · 2026-09-25T13:39:03-0400

exnisstech said:
It definitely increased growth in my tank. I no longer had to look at before and after pics to see growth. After two months I had increased my AFR from 35ml daily to 60ml. I'll link a very good article on pH and toward the bottom of the article it tells how to perform an aeration test to determine if lower pH is being caused by elevated indoor CO2 or something else. The outside airline will only help if elevated indoor CO2 is the cause but it's the most common cause I believe.

https://www.reef2reef.com/ams/understanding-ph-in-reef-tanks-part-one.1133/

Thank you! Do you run a CO2 scrubber by chance between the outside airliner and skimmer ?

exnisstech · 2026-09-25T13:54:59-0400

Kika said:
Thank you! Do you run a CO2 scrubber by chance between the outside airliner and skimmer ?

I do not. TBH I wasn't really concerned about increasing growth. The tank was doing fine but I got bored one day and had a skimmer on the shelf so I hooked up just to see how much of a difference it would make. I moved into a new tank 2 months ago and changed skimmers but haven't bothered to connect an outside airline. I don't frag so I don't really need accelerated growth so I'm not planning to reconnect it at this time.

Peer.Boerner · 2026-09-25T14:16:18-0400

I have a 50 net gallon mixed reef (LPS and simple SPS). I run a co2 scrubber plumbed to outside air. I run Kalk at night and AFR during the day. My Kalk is dosed at 700ml and I make up any remaining top off water with an ATO. During the day I dose 12ml of AFR in 3 doses. I dose Mg daily by hand. Day time pH 8.12 -8.30. Night 8.12. Not sure Kalk makes that much of a ph diffference but (1) the coral looks great. (2) The chemistry is right where I want. (3) I use so little AFR it’s very inexpensive. Last Saturdays measurements: Alk 9.5, CA 465, mg 1410 (don’t tell @Randy Holmes-Farley i measure it just because I have left over Salifert reagents :) ). The numbers stay very very consistent.

t5Nitro · 2026-09-25T14:38:14-0400

My AFR is dosed 8x during photoperiod. Kalkwasser dosed every 9 minutes around the clock. I got to fairly high AFR requirements and decided to add kalkwasser on a pump. My top off water then scales down as I increase kalkwasser dosing.

Otago · 2026-09-25T14:39:20-0400

In theory you will miss out on the balanced trace of AFR because some of your alk/cal demand will come from the kalk rather than AFR but it may not be a problem in reality. If you figure out the percentage of AFR alk addition to Kalk alk addition you could dose Tropic Marin A+K to make up the difference, but your ICPs will tell you everything.

Dr4gula.f32 · 2026-09-25T14:41:47-0400

I am also interested in making this work. I am dosing 73ml of AFR daily and every week I have to increase it 1 or 2 ml. During the day my PH is about 8.2 but at night it dips to around 7.7

Kika · 2026-09-25T15:46:24-0400

Otago said:
In theory you will miss out on the balanced trace of AFR because some of your alk/cal demand will come from the kalk rather than AFR but it may not be a problem in reality. If you figure out the percentage of AFR alk addition to Kalk alk addition you could dose Tropic Marin A+K to make up the difference, but your ICPs will tell you everything.

Yeah. So this leave the doors open for kalk + A4R or another dosing method that can integrate with kalk. So maybe I’m thinking Kalk + 2 part such as Sodium Bicarb & Calc chloride where I can mix them with TM A&K. I don’t need Mag as I do a lot of water changes, plus Mag testing is not accurate

Peer.Boerner · 2026-09-25T15:50:25-0400

Kika said:
Yeah. So this leave the doors open for kalk + A4R or another dosing method that can integrate with kalk. So maybe I’m thinking Kalk + 2 part such as Sodium Bicarb & Calc chloride where I can mix them with TM A&K. I don’t need Mag as I do a lot of water changes, plus Mag testing is not accurate

Agree on Mg testing hence my joking comment to Randy. He convinced me not to test Mg but I will until I run out of reagent. That said I calculated my Mg dose to match the amount of Ca I’m adding with the fixed amounts of Kalk and AFR.

Kika · 2026-09-25T15:53:47-0400

t5Nitro said:
My AFR is dosed 8x during photoperiod. Kalkwasser dosed every 9 minutes around the clock. I got to fairly high AFR requirements and decided to add kalkwasser on a pump. My top off water then scales down as I increase kalkwasser dosing.

Sweet, so they can both be dosed fairly closed (~10 min apart)… makes total sense as A4R may have a delayed chemical reaction due to organic components… this means that I can distribute the kalk over 24 hrs which may push ph even further during photoperiod. Excellent !!

areefer01 · 2026-09-25T15:57:57-0400

Kika said:
Yeah. So this leave the doors open for kalk + A4R or another dosing method that can integrate with kalk. So maybe I’m thinking Kalk + 2 part such as Sodium Bicarb & Calc chloride where I can mix them with TM A&K. I don’t need Mag as I do a lot of water changes, plus Mag testing is not accurate

I wouldn't over complicate it. Also I probably would not spread AFR over the complete light on cycle. There really is no need to spread it out. I dose 100 ml over the course of an hour early morning after a bit of lights on.

You can play with adding kalkwasser yet still let AFR do the heavy lifting.

Randy Holmes-Farley · 2026-09-25T16:03:05-0400

I think it’s a fine way to go to use AFR and kalk, but I would caption that you may notice no tank difference, and even just the pH value takes a fair amount of alk via hydroxide to make a noticeable difference. A little kalk won’t be significant.

t5Nitro · 2026-09-25T16:06:35-0400

Here's a good point. To expand further on my kalkwasser addition to AFR, I started by adding 2-3L daily and am somewhere around 1 gallon per day now. This is dosed all day long using a spectrapure pump. This is dosed into 150-170 system gallons, so it is still a fairly small amount and may or may not be beneficial. I still need to dose 2-part alk and calcium on top of it all. I fine tune the final numbers with the 2 part and fix the first two dose volumes at this point.

Randy Holmes-Farley said:
I think it’s a fine way to go to use AFR and kalk, but I would caption that you may notice no tank difference, and even just the pH value takes a fair amount of alk via hydroxide to make a noticeable difference. A little kalk won’t be significant.