Understanding Alkalinity

[Alan]

One of the most confusing aspects of keeping corals for reef keepers is alkalinity, here is a description of what it is and how the relationship works with calcium and Ph, a must read for all reef keepers with LPS or SPS corals.

''To safely avoid dangerous imbalances in the Ca-Alk dynamic, aquarists simply need to avoid pushing either component to an extreme end or both simultaneously high. Instead, think of the relationship as a Hi-Lo situation within the safe ranges. Within the accepted ranges (350-450 ppm Ca and 8-12 dKH Alk), one parameter can be pushed to a high end while the other is allowed to stray toward the middle or lower end. Any reasonably mix of the two will still provide more than enough of both elements for successful calcification'' Quote from an article by Anthony Calfo on wetwebmedia.

Entire article here.
http://www.wetwebmedia.com/calcalkmar.htm

 

[Ridwaan]

Heres another link about alkalinity

http://www.advancedaquarist.com/2002/2/chemistry

 

[ShaneW]

Great info... Thanks

 

[Prodigy]

Hey guys
Great thread thanx so if i can keep my temp, salinaty and pH stable the other parameters will fall into place(been a young tank with not alot of livestock and corals)

 

[Alan]

Uhm not really your PH depends on the amount of Alk present in the water and when you add alk you have to add an equal amount of calcium to keep it in balance.

 

[silver phanton]

 

[shrimp]

Uhm not really your PH depends on the amount of Alk present in the water and when you add alk you have to add an equal amount of calcium to keep it in balance.

Alan, still new and trying to understand water chemistry .... I want to increase my CA and KH (alk) but do not want to induce precipitation .... is there a buffer that increases both CA + KH .... for better understanding, heerwith my parameters:

SG: 1.025
Temp: 26.5
PH: 8.3
KH: 7 (little too low)
CA: 340 (too low)

I perform weekly WC using Reef Crystals and only have a few shrooms so CA usage fairly low ..... am I correct that too maintain your Alk + CA your MG must be certain level (think 1,200 range)

thanks

 

[Mekaeel]

Shrimp. The best way to raise your Ca, is by dosing Calcium Chloride. To raise your Alk, you dose Bicarb. Once the desired levels are reached, maintain it using kalk (Calcium Hydroxide). Kalkwasser doses Ca and Alk together.

 

[davidfr7]

Total Alkalinity = total of all alkaline chemicals in water. The measure of water's ability to prevent pH change.

Effects of low Alkalinity = pH bounce and increased corrosion
Effects of high Alkalinity = High pH and Bicarbonate scale.

18g Bicarb to a 1000 l of water will raise TA by 10ppm.

 

[Floyd]

Alkalinity assistance needed

Hi,

I need assistance to reduce my dkh in my Redsea Max. I would like to stabilize parameters in order for me to add coral.

My current parameters:

SG: 1.024
Temp: 25 (chiller connected to control temp)
PH: 8.0
Dkh14, alk meq 5.25
CA: 420
Mag 1280
Nitrate 25
Phos 0.5

Notes:
I have installed a reactor with bio pellets in the DT a week ago.
Filtering: carbon bag, Orca cubes with a airstone in the 1 compartment.
Tank is running for approx 3 months.

What can I use to reduce Dkh/ Alk?

 

[mytank]

Hi,

I need assistance to reduce my dkh in my Redsea Max. I would like to stabilize parameters in order for me to add coral.

My current parameters:

SG: 1.024
Temp: 25 (chiller connected to control temp)
PH: 8.0
Dkh14, alk meq 5.25
CA: 420
Mag 1280
Nitrate 25
Phos 0.5

Notes:
I have installed a reactor with bio pellets in the DT a week ago.
Filtering: carbon bag, Orca cubes with a airstone in the 1 compartment.
Tank is running for approx 3 months.

What can I use to reduce Dkh/ Alk?

KH is one of those you can't add much to reduce it, water changes help but slowly reduce the KH.

How are you getting your KH to that level are you dosing or what salt you using.

Your three options are:

Stop dosing KH

If its a salt with high KH - change salt

Do 20% water changes (provided its not the salt) every two to three days for a two weeks.

Make sure your WC water has a KH of 7 - 8.

Only other option is run some aggressive GFH amounts as GFH is known to leech KH but I would suggest against this as it will strip all P04 out

 

[Nemos Janitor]

If you raise your salinity to S=35 with a good brand of salt mix, your Ca and Mg will rise and your KH will fall.

 

[mytank]

If you raise your salinity to S=35 with a good brand of salt mix, your Ca and Mg will rise and your KH will fall.

What's that in 1025 terms?

 

[Bendor]

Very helpful, thanks!

 

[Nemos Janitor]

1.0265 @ 20c. I am assuming the use of a refractometer was used to obtain the SG 1.024. and that the SG 1.024 was at 20c

 

[mytank]

1.0265 @ 20c

Is it a reaction that takes place,precipitation?

 

[Floyd]

Alk

I used Salinity salt and then changed to Reef salt.

Can this be the reason why alk/ dkh is so high?

 

[mytank]

I used Salinity salt and then changed to Reef salt.

Can this be the reason why alk/ dkh is so high?

Salinity is bang on 7kh but they do buffer with baron (think that's the spelling) which does throw off some test kits like a Hanna for example.

Reef salt I am not sure you should test the water, I know salts like Reef Coral Pro has a KH of 12 ...

 

[Nemos Janitor]

is it a reaction that takes place,precipitation?

yes

i used salinity salt and then changed to reef salt.

Can this be the reason why alk/ dkh is so high?

yes

 

[carlosdeandrade]

As long as your pH doesn't rise above 8.6 you will be fine, otherwise you will need to do a few small water changes to get it down. Just monitor the pH everyday, especially during the day.