Muriatic acid to lower KH in new saltwater mix for waterchange

[Macropora]

Boomer,

How critical is it to maintain the same exact parameters for a water change specifically carbonate hardness/alkalinity? For example my reef system has a dKH of 11.2 and the saltwater I mix has a dKH of 13.2. Changing 25 gallons of saltwater on a 170 gallon system weekly. I know that the dkh will go up a bit. If the water change was larger like 50% of the tank volume then the change would be much larger and may stress the corals. Was thinking of using muriatic acid to lower the KH to the same exact parameter found in the tank. Is muriatic acid easy to use and how much would you use for 25 gallons of saltwater? Heard it being used for pools, just wondering if it's worth it and can it be applied the same way for our saltwater reef tanks.

Carlos

 

[Boomer]

What salt are using ?

25gal*13.2+11..3*145gal / 170 gal = 11..5 dKH

Adding Muriatic acid will also lower the pH

11.3 vs 11.5 will have little effect, if any.

 

[Boomer]

And you should not be runing a Alk over 11 dKH to begin with, there is no reason to.

 

[Macropora]

What salt are using ?

25gal*13.2+11..3*145gal / 170 gal = 11..5 dKH

Adding Muriatic acid will also lower the pH

11.3 vs 11.5 will have little effect, if any.

Reef Crystals

 

[Macropora]

And you should not be runing a Alk over 11 dKH to begin with, there is no reason to.

Trying to bring the dKH down gradually. Getting two different readings with two different test kits.

Salifert = 11.2 dkh

Hannah Alkalinity checker = 10.1 dkh

If I use the Salifert then I'm over, but when I use the Hannah then I'm okay. Which is more accurate?

 

[Boomer]

OK Mac RC has a dKH of about ~ 13. So, as I expected the Salifert is correct i.e. 11..5 (calculating above) dKH vs 11.2 dKH ( Salifert). You may want to think about switching salts, as your Alk demand is very low or is it you are running a calcium reactor and using RC ?

 

[Macropora]

OK Mac RC has a dKH of about ~ 13. So, as I expected the Salifert is correct i.e. 11..5 (calculating above) dKH vs 11.2 dKH ( Salifert). You may want to think about switching salts, as your Alk demand is very low or is it you are running a calcium reactor and using RC ?

Been using RC for many years and a Calcium reactor. I recently purchased Instant Ocean hoping the dKH would be lower. It's actually even higher than the RC using the Salifert Test Kit! Maybe that's an anomaly. That's why I was thinking of using muriatic acid to bring down the dKH since I have so much salt left to use.

 

[Boomer]

It should be lower by 2 dKH. Do you roll the container or mix the bag well before using ? What is your calcium level with the reactor ? You need no higher than 410-420. If it is like 440 or so turn down the reactor to 420, that will drop the dKH by 2.8 dKH.

 

[Macropora]

It should be lower by 2 dKH. Do you roll the container or mix the bag well before using ? What is your calcium level with the reactor ? You need no higher than 410-420. If it is like 440 or so turn down the reactor to 420, that will drop the dKH by 2.8 dKH.

That's what I thought... It should be around 11 dkh.

Honestly never thought of rolling the bucket or shaking the bag before using. I'll try it for future water changes.

Calcium level is around 470 ppm with the Calcium Reactor. I've increased the drip rate and the resulting Ca and dKH has slowly been dropping.

Thanks for the advice Boomer. Really great having a resident chemist to ask for help on MR. Thanks again.

 

[Boomer]

Yah, there is no reason to have a Ca++ of 470 with a reactor or even without one. For each 20 ppm Ca++ drop the Alk drops 2.8 dKH. But there are other issues here as you are using a salt which you should not really be using that has a Ca++ 490 ppm (RC) and a reactor and your tank does not have that kind of Ca++ or Alk demand to be using both. So, it is change to IO ( Ca++ ~ 400 ppm) or shut-down that reactor or see if you can tweak that reactor.

 

[Macropora]

Yah, there is no reason to have a Ca++ of 470 with a reactor or even without one. For each 20 ppm Ca++ drop the Alk drops 2.8 dKH. But there are other issues here as you are using a salt which you should not really be using that has a Ca++ 490 ppm (RC) and a reactor and your tank does not have that kind of Ca++ or Alk demand to be using both. So, it is change to IO ( Ca++ ~ 400 ppm) or shut-down that reactor or see if you can tweak that reactor.

Switching to IO to see how that works for the next several water changes. Thank you for your help!

 

[ed4]

No problem - nothing to it!