Alk at consistent 6.4 - should I adjust?

[CloudReefer]

Hello

I noticed that an encrusting SPS coral I have is not doing well so I did a full run of tests and found my alk was dropping consistently between water changes. The original mix was 7.2 and it now stays between 6.4-6.6. 10%+ weekly water changes don't seem to be enough to keep it around 7.

I use Tropic Marin Pro Reef and these parameters have stayed steady since I started the tank, except alk. Not 100% sure about nitrate and phosphate though as I do have some GHA and sometimes my tests read 0. Perhaps fluctuating nutrient levels could be contributing to the declining SPS health?

SG 1.025
pH 8.2
Ca 390
Alk 6.4
Mg 1230

Should I raise alk to ~7.0 and keep it there?

Thanks!

 

[Townes_Van_Camp]

Yes, no more than 1.0 to 1.4 dkh per day (depending on who you ask).

Dose magnesium up first, Then chase alk why not 8-9?

 

[CloudReefer]

Yes, no more than 1.0 to 1.4 dkh per day (depending on who you ask).

Dose magnesium up first, Then chase alk why not 8-9?

Mg is 1230 and I only have a few small corals that came on my live rock. Ca and Mg haven't moved and water changes seem to be sufficient to maintain those levels.

NSW is around 7.0 that's why. Just keeping things simple as this is my first tank in a long while.

 

[Townes_Van_Camp]

Mg is 1230 and I only have a few small corals that came on my live rock. Ca and Mg haven't moved and water changes seem to be sufficient to maintain those levels.

NSW is around 7.0 that's why. Just keeping things simple as this is my first tank in a long while.

Just my opinion of course.

1230 is low, slightly. A little extra magnesium never hurt anything. But not enough and you will never get alk stable. It's better to lean towards more than not enough.you gotta have mag to uptake all and cal.

In regards to Alk, the ocean can do 7.0 because it can keep that stable. I know I can't keep a perfect 7.0. So basically as soon as I dose, I'm back into the territory where I'm dosing it back up. At 8 or 9 you have some leeway.

Lots of smarties here that can explain it way better than I can.

 

[Salty_Northerner]

I've learned in my own tank recently using the same salt that keeping the mag at 1400 seems to hold calcium and ALK. The alk will fall a .1-.2 between water changes.

The higher the magnesium on a scale will also lift cal and alk. @Lou Ekus

He has a video on YouTube explaining how it works. Watch from 13:45 and you can see how he demonstrates the relationship.

 

[X-37B]

An alk of 7 is fine. I run 6.5-7.5 and target 7.
Get a 2 part and start dosing by hand daily to keep alk and ca stable.
You could try A4R if your system is small.
Ca 400-450, 420 target.
I run mag at 1300-1400, 1350 target.
You can dose mag by hand to keep it stable.
I use dsr trace that keeps mag and K stable.

 

[CloudReefer]

Thanks for all of the great advice everyone! I'll have to check the video out when I get home from work.

I've only ever dosed kalk before, so not really familiar with the 2 part systems. What is A4R?

I have a 75g tank with a 20g sump. Happy to dose by hand as long as it is practical.

 

[X-37B]

Thanks for all of the great advice everyone! I'll have to check the video out when I get home from work.

I've only ever dosed kalk before, so not really familiar with the 2 part systems. What is A4R?

I have a 75g tank with a 20g sump. Happy to dose by hand as long as it is practical.

A4R is a 1 part that handles alk, ca, mag, and others.
I use it in my 20g nano cube.
2 part adds alk and ca.
Kalk can supply both too and should work on your system.

I use esv 2 part also and its simple.
I dose by hand twice a day.
I dosed once a day until I got to 30ml a day then I split it to 15ml 2x a day.

If you have a low demand large tank A4R will work well. My 20g is high demand and uses 17ml 2x a day so 34ml total.
The max dose they recommend is 25ml per 25 gals so im already over max with no issues. With a large system, like my 80/30, it may not be cost effective. I run a carx on it and dose 2 part on my 45.

 

[CloudReefer]

A4R is a 1 part that handles alk, ca, mag, and others.
I use it in my 20g nano cube.
2 part adds alk and ca.
Kalk can supply both too and should work on your system.

I use esv 2 part also and its simple.
I dose by hand twice a day.
I dosed once a day until I got to 30ml a day then I split it to 15ml 2x a day.

If you have a low demand large tank A4R will work well. My 20g is high demand and uses 17ml 2x a day so 34ml total.
The max dose they recommend is 25ml per 25 gals so im already over max with no issues. With a large system, like my 80/30, it may not be cost effective. I run a carx on it and dose 2 part on my 45.

Do you use the liquid or the powdered form of A4R?


Looking at either this
Tropic Marin All for Reef Powder 800g https://a.co/d/eFosqx0

or


Tropic Marin USA All-for-Reef 1000 ml https://a.co/d/86Jtb48



Thank you for the advice!

 

[X-37B]

I use the powder.