Time To Dose Kalk - Alk Low

[bzb]

I think I'm going to start mixing up Kalkwasser in my ATO. Tested twice today, but not sure what's going on here.

Alk dropped to ~6.3 dkh, Mg dropped to ~1284, but my Ca is holding steady at 460. Tank is fallow. Water change is ~8% weekly (5 gallons) on Sundays. I'm running IO Reef Crystals on RODI testing at 0 TDS.

pH: 8.1
Temp: 78
sg: 1.024
Nitrate: ~0
Alk: 6.3
Ca: 460
Mg: 1284

Last week's values:
pH: 8.1
sg: 1.024
Nitrate: <5ppm
Alk: 7.2
Ca: 460
Mg: 1524

Stock:
LPS: 3 head torch, two 1" plate corals
SPS: Tiny Monti frag (1" square) and a 5x2" Monti Cap.
Softies: Leather is pretty good size now, handful of mushrooms and zoas (nothing huge) and a pretty rapidly growing GSP frag.
CUC: about two dozen hermits, two large turbos, two emeralds, and a tank full of pods.

Thoughts?

 

[jcook54]

I'm assuming the stock list is for corals you have in the tank? You mention in the first paragraph that it's "fallow" and I've always taken that to mean there isn't anything in the tank. I think you're using a bit of both in equal amounts and the water changes aren't replenishing in equal amounts. I've used Reef Crystals for years and have always found the Alk levels in freshly mixed saltwater to vary by quite a bit. Everything you read says Reef Crystals has such a high alk content but I've never ever tested fresh saltwater over 9.0 dKh and have tested it as low at 5.4 dKh (yes I tested twice with 2 different kits because the reading was so low). I took a look at my log and the average Alk for freshly mixed Reef Crystals is around 7.0 dKh.

I'd also point out that the test kits we use are good but not without their faults. I'm a Salifert user, what kits do you use? I'd be willing to bet if I came over and tested your water with fresh Salifert kits they'd be close but not right on given the accepted margin of error in hobby grade kits.

 

[jcook54]

Sorry, I'm well caffeinated and meant to say one other thing. At this point, I would manually dose Alk. I did it that way for years and with the drop you're seeing, you'd only really need to dose once or twice a week. Kalk in you ATO is a great way to dose Alk but it has some pretty significant downside if you don't have a pH monitor that can cut the pump off.

 

[bzb]

I'm assuming the stock list is for corals you have in the tank? You mention in the first paragraph that it's "fallow" and I've always taken that to mean there isn't anything in the tank. I think you're using a bit of both in equal amounts and the water changes aren't replenishing in equal amounts. I've used Reef Crystals for years and have always found the Alk levels in freshly mixed saltwater to vary by quite a bit. Everything you read says Reef Crystals has such a high alk content but I've never ever tested fresh saltwater over 9.0 dKh and have tested it as low at 5.4 dKh (yes I tested twice with 2 different kits because the reading was so low). I took a look at my log and the average Alk for freshly mixed Reef Crystals is around 7.0 dKh.

I'd also point out that the test kits we use are good but not without their faults. I'm a Salifert user, what kits do you use? I'd be willing to bet if I came over and tested your water with fresh Salifert kits they'd be close but not right on given the accepted margin of error in hobby grade kits.

Correct, it's fishless but inverts are still in the tank.

Good point - I'll test the water change tomorrow before adding it. I'm using both Salifert and Rikka tests to verify.

 

[bzb]

Sorry, I'm well caffeinated and meant to say one other thing. At this point, I would manually dose Alk. I did it that way for years and with the drop you're seeing, you'd only really need to dose once or twice a week. Kalk in you ATO is a great way to dose Alk but it has some pretty significant downside if you don't have a pH monitor that can cut the pump off.

I'm running a Tunze ATO with the timer on the low setting, so the most it could add at any given time is about 1 gallon before triggering fault (~75 gallons total system volume). Think it's still too risky?

 

[jcook54]

I have the same setup x2 (Tunze ATO, 70-ish gallons) and I never went that route because it was too risky for me given the option to manually dose was cheap and easy. I personally would never dose Kalkwasser without have a pH monitor that could kill the outlet but a lot of people do without issue. In you case (and mine) it just seems like manually dosing a product like Reef Builder has zero risk and isn't hard at all. I only recently switched to dosing pumps because I got tired of dosing every. single. stinkin'. day.

 

[ichthyoid]

Also, how long has your tank been up?
Reason I ask is that new tanks tend to consume more alkalinity than calcium, then eventually begin to equal out.
Your magnesium drop may be going into coralline algae growth.

fwiw, I had not heard of Rikka test kits, but they appear to be from the Ukraine-

Rikka test kits?

Anyone have experience with Rikka test kits? They seem fairly new, but look nice. I am thinking about trying them out, I'll let everyone know how it goes. https://www.ebay.com/itm/RIKKA-SALTWATER-REEF-TEST-KIT-Ca-Mg-KH-ALKALINITY-CALCIUM-MAGNESIUM/312578976139

www.reef2reef.com

 

[bzb]

Little less than 3 months, so I guess it's new tank munchies.

So is it better just to dose the Reef Builder for now, and when I start seeing the Ca consumption move to kalk?

 

[jcook54]

I would not dose kalk without some sort of controller to monitor pH. If I were you, I'd test and manually dose since the uptake is so low. Check it out - with regular testing and manual dosing there almost 0 risk. You test, you dose. With kalkwasser, if you don't have a controller, there's some risk of quickly skyrocketing the pH of the tank. How much risk? Probably not all that much but why take the risk when there's a simple alternative that has next to none? I'll tell you why - cost. Kalk is a great way to maintain calcium and alkalinity in a tank and it's cheap when compared to dosing large quantities of 2 part. But right now, there's isn't much savings at all since you would be dosing something like a teaspoon of Reef Builder once or twice a week.

One way of dosing kalk that I was comfortable with was a very small amount in my ATO to give me some Ca/Alk additions but I still would test and dose manually to get the levels where I wanted them. The goal was to save $$$ on dosing 2 part while still being fairly "safe" with a relatively small amount of kalk in the ATO. I stopped doing that because it was kind of a pain and I switched to BRS 2-Part which is pretty cheap.

To answer your question more directly - you would not want to start dosing kalk with high calcium. With your calcium levels at 460, it wouldn't take much to start pushing that number up too high.

 

[bzb]

FYI: after mixing overnight, my Reef Crystals water is measuring at 9.6 dkh.

 

[bzb]

I'm noticing growth in the GSP (duh) and xenia (also duh) but also a good bit of growth on my hammer. I can't really tell if my montis are growing. I'm not noticing any coralline growth, but there's other signs of tank health such as the numerous pods, worms, sponges, etc.

I think the numbers are fairly stable without dosing anything yet - just the weekly water changes. I'm about to do one today, in fact.

Based off the last two weeks measurements, I believe my water changes are sufficient at this time, but obviously would like more growth (especially would like to see some coralline!!) so any suggestions are appreciated!

11/16
pH: 8.1
Temp: 78
sg: 1.024
Nitrate: ~0
Alk: 7.2
Ca: 440
Mg: 1176

11/24
pH: 8.1
Temp: 78
sg: 1.025
Nitrate: ~0
Alk: 6.9
Ca: 420
Mg: 1188

 

[Cook]

I would not dose kalk without some sort of controller to monitor pH. If I were you, I'd test and manually dose since the uptake is so low. Check it out - with regular testing and manual dosing there almost 0 risk. You test, you dose. With kalkwasser, if you don't have a controller, there's some risk of quickly skyrocketing the pH of the tank. How much risk? Probably not all that much but why take the risk when there's a simple alternative that has next to none? I'll tell you why - cost. Kalk is a great way to maintain calcium and alkalinity in a tank and it's cheap when compared to dosing large quantities of 2 part. But right now, there's isn't much savings at all since you would be dosing something like a teaspoon of Reef Builder once or twice a week.

So is dosing Kalk without a pH controller worse than using 2 part dosers on timers without a controller in your opinion? I was looking at going the Kalkwasser route attached to ATO also.

 

[jcook54]

I dose 2 part because I feel it's safer and my pH is good and stable. A $60 Jabao doser and $40 worth of the 2 part of your choice and you're on your way.

Let me be completely honest - there are lots and lots of people who add kalkwasser to their ATO and have zero negative effects. It's just not very easy to "control" in the sense that it's hard to determine exactly what you're adding to your system. Topoff water demand fluctuates and adding water to the top off container is regularly diluting the mix. Add to that the fact that there's a very real potential to cause some serious pH issues and I don't do it. When I do dose kalkwasser, it's with a dedicated kalk stirrer that's controlled with a pH probe so I know exactly what I'm adding and it'll shut of if there's any issue. Even if the risk is nominal, for $100 you can dose 2 part and not incur even that nominal risk.

 

[bzb]

I pulled the trigger on a Hanna pH tester right before Thanksgiving, and I'm holding pretty stable at 7.8 (curiously, the API test always shows between 8.0 and 8.2). The Hanna checker calibrated properly with the included solutions.

Right after I got the Hanna checker, I tested the water and noticed my Alk dropped from 7.2 after the water change to 6.9 in less than two days. I started dosing a small amount of Reef Builder (1/4 tsp mixed with a cup of RO) every couple days to slowly raise it. At the rate I'm testing, I'm looking at dosing about 1.5 tsp of Reef Builder per week to keep around 7.5dkh.

Current values (with new equipment!):
pH: 7.8
Temp: 78
sg: 1.025
Nitrate: 0 (tested on API and Gieseman high res)
Alk: 7.8 (tested on Rikka and Salifert)
Ca: 420
Mg: 1068

I'm still not growing any noticeable coralline, but the softies are certainly growing/reproducing. SPS are still too small for me to notice, but I've got OK polyp extension.

Perhaps it is indeed time to start dosing two part...

 

[ZapataInc]

I pulled the trigger on a Hanna pH tester right before Thanksgiving, and I'm holding pretty stable at 7.8 (curiously, the API test always shows between 8.0 and 8.2). The Hanna checker calibrated properly with the included solutions.

Right after I got the Hanna checker, I tested the water and noticed my Alk dropped from 7.2 after the water change to 6.9 in less than two days. I started dosing a small amount of Reef Builder (1/4 tsp mixed with a cup of RO) every couple days to slowly raise it. At the rate I'm testing, I'm looking at dosing about 1.5 tsp of Reef Builder per week to keep around 7.5dkh.

Current values (with new equipment!):
pH: 7.8
Temp: 78
sg: 1.025
Nitrate: 0 (tested on API and Gieseman high res)
Alk: 7.8 (tested on Rikka and Salifert)
Ca: 420
Mg: 1068

I'm still not growing any noticeable coralline, but the softies are certainly growing/reproducing. SPS are still too small for me to notice, but I've got OK polyp extension.

Perhaps it is indeed time to start dosing two part...

I bought some BRS 2 part during their black Friday sale and found a 4 head Jebao wifi dosing pump that will be delivered tomorrow. So I'm going to start dosing. I don't know why I'm a little anxious. Lol

 

[bzb]

So I've had a good couple weeks of dosing Reef Builder every couple days and trying to keep my Alk stable. I think I've achieved this, testing alk every couple days it seems to stay in the mid 8's (fluctuating a bit between 8.2 and 8.6). Calcium seems to be dropping way slower than Alk - I'm still testing at 420 and it hasn't really dropped much at all.

However, I've tested my pH throughout the day with the Hanna checker, and I've never gotten a reading above 7.9. I know 8.3 is the sweet spot, but I hesitate adding Reef Buffer... it's likely the CO2 I'm injecting with my oversized skimmer, but I also would prefer not adding a CO2 scrubber.

Would dosing two part be significantly different in raising my pH than the Reef Builder dosings?