ALK dropping - should I just keep upping the ALK dosage?

[JvC]

Hello,

I have a 300 gallon mixed reef that has been setup for about 5 or 6 weeks. My ALK started dropping a couple days ago. It went from 8.7 and is now at 8.3. I have increased ALK dosing considerably. Up from 128 to 175 ml per day - and ALK is still in decline.

I am using Tropic Marin 3 part.

Is it odd, that I am dosing so much more ALK than CAL and MAG?

I am mixing a new batch of part B to see if something is wrong with that. I see no precipitation. And I checked that the ALK is flowing correctly through the DOS.

Should I just keep increasing ALK doseage to cath the fall? I usually run about 8.75 or so.

Thanks,
jvc

 

[Randy Holmes-Farley]

I’d increase both alk and calcium equally to meet alk demand, and dose the part C at the recommended rate regardless of any measurement.

 

[JvC]

I’d increase both alk and calcium equally to meet alk demand, and dose the part C at the recommended rate regardless of any measurement.

Won't that drive the calcium up?

 

[Randy Holmes-Farley]

Won't that drive the calcium up?

Not so you could notice. It won't even come up to normal.

Alk 8.28 --> alk 8.7
calcium in same volume 407 ppm to 410 ppm (3 ppm increase)
magnesium at the appropriate extra rate: 1326 --> 1326 ppm (less than 1 ppm increase)

 

[STEEZY]

Have you tested alk with multiple types of tests?

 

[lubeck]

I don’t dose my bionic equally either. Hope that doesn’t screw things up. I’ve found when I run it equal my calcium goes to 500

daily dosing
18 ml alk
8.5 ml cal
22 ml mag
1250 ml kalk.

 

[Randy Holmes-Farley]

I don’t dose my bionic equally either. Hope that doesn’t screw things up. I’ve found when I run it equal my calcium goes to 500

daily dosing
18 ml alk
8.5 ml cal
22 ml mag
1250 ml kalk.

View attachment 3002464

In your case the answer may relate to the kalkwasser, which alone will slowly raise calcium if used to maintain alkalinity.

I used a lower calcium salt mix to offset that issue. This is form an article of mine:

Calcium (Ca). In my reef aquarium, I use only Instant Ocean salt and I have not added any additional calcium except as limewater for a number of years (during which time I have continued regular 1% daily water changes). So why is my calcium level (472 mg/L) higher than one would normally expect for Instant Ocean (maybe between 350 and 400 mg/L)? That long term rise in calcium is actually the expected result when using limewater to maintain alkalinity.

Limewater adds calcium and alkalinity in exactly the same proportions as in pure calcium carbonate. So if that is what is used by corals to make skeletons, and what precipitates on pumps and such, then calcium would stay constant.

But both magnesium and strontium get into growing calcium carbonate crystals in place of some of the calcium. A few percent of the calcium is replaced this way. Consequently, since the same amount of alkalinity (the carbonate) is used over time, and somewhat less than the balancing amount of calcium, calcium rises if alkalinity is maintained. I’m happy to see the result match the theory, and the calcium level seems fine to me.

 

[arafas]

I don’t dose my bionic equally either. Hope that doesn’t screw things up. I’ve found when I run it equal my calcium goes to 500

daily dosing
18 ml alk
8.5 ml cal
22 ml mag
1250 ml kalk.

View attachment 3002464

could this be calibration of the doser issue? I dose equal parts and calc doesnt creep up.

 

[lubeck]

could this be calibration of the doser issue? I dose equal parts and calc doesnt creep up.

Maybe but I think as Randy said it’s probably from the kalk. I can do a calibration to confirm

 

[JvC]

Not so you could notice. It won't even come up to normal.

Alk 8.28 --> alk 8.7
calcium in same volume 407 ppm to 410 ppm (3 ppm increase)
magnesium at the appropriate extra rate: 1326 --> 1326 ppm (less than 1 ppm increase)

I had no idea. Good info. Thanks

 

[JvC]

I know that it is ok to dose ALK and CAL (Parts B and A, respectively) at different rates, but I may not need to based on what Randy said.

I am going to increase may Calcium. I will also increase the MAG (part c) to equal to the calcium, since it is the lessor of the Cal and ALK being dosed.

I tried a different solution of Part B and there was no noticable difference. I am increasing the amount dosed of ALK and CAL today.

 

[Randy Holmes-Farley]

I know that it is ok to dose ALK and CAL (Parts B and A, respectively) at different rates, but I may not need to based on what Randy said.

I am going to increase may Calcium. I will also increase the MAG (part c) to equal to the calcium, since it is the lessor of the Cal and ALK being dosed.

I tried a different solution of Part B and there was no noticable difference. I am increasing the amount dosed of ALK and CAL today.

Let us know what happens going forward!

 

[JvC]

Let us know what happens going forward!

It has been a couple of weeks, and I have slowly brought the ALK levels up. There was no issue, just the tank seems to be using more. Based on your advice, Randy, I started dosing ALK, CAL, and MAG parts equally and raised my ALK back to the 8.75 or so it was at. I am now dosing equally (175 ml per day) and the levels seem to be stable.

Thanks!

 

[I never finish anythi]

Have you tested alk with multiple types of tests?

I wouldn't recommend using multiple tests , you will get the run around and end up chasing your tail!

 

[STEEZY]

I wouldn't recommend using multiple tests , you will get the run around and end up chasing your tail!

I simply meant to confirm that his testing is accurate or in line.

 

[Randy Holmes-Farley]

It has been a couple of weeks, and I have slowly brought the ALK levels up. There was no issue, just the tank seems to be using more. Based on your advice, Randy, I started dosing ALK, CAL, and MAG parts equally and raised my ALK back to the 8.75 or so it was at. I am now dosing equally (175 ml per day) and the levels seem to be stable.

Thanks!

View attachment 3028255

Thanks for the update!

Happy Reefing!