Ca/Alk balance with red sea foundation liquid

[Mrzak92]

What ratio do i use to balance alk and ca using red sea foundation liquid A and B my tank is approximately 42 gallons and would like to raise my alk from 8dkh to 9 dkh without reducing my calcium which is currently 425 ppm currently and would like to keep it there. Fyi my mg is 1350ppm. As far as i am aware im not meant to dose 1:1 as they are different concentration

 

[Randy Holmes-Farley Verified Community Expert]

Correct, they are not designed for 1:1 dosing.

Balanced dosing is about 18-20 ppm calcium for each 2.8 dKH of alkalinity

For calcium: Liquid supplement: 1ml will raise the Ca level of 100 liters (25 gal) by 2ppm.
For alkalinity: Liquid supplement: 1ml will raise the Alk level of 100 liters (25 gal) by 0.036 meq/l (0.1dKH)

In a 25 gallon tank,

28 mL gives 2.8 dKH
9.5 mL will give 19 ppm calcium

Thus I would dose alkalinity as needed, and then dose 9.5/28 = 34% as much of the calcium part. Adjust the calcium every so often if it seems to be rising or falling too much.

 

[ariellemermaid]

Every tank is different though. For instance my 20g coral invert tank initially only used up alk until I had a large birdsnest and dosed both but never 1:1. Then it up and died one day. So I’m back to where I started; Ca basically stays level but I do need daily Alk. Haven’t needed To dose calcium in months.

 

[Randy Holmes-Farley Verified Community Expert]

Every tank is different though. For instance my 20g coral invert tank initially only used up alk until I had a large birdsnest and dosed both but never 1:1. Then it up and died one day. So I’m back to where I started; Ca basically stays level but I do need daily Alk. Haven’t needed To dose calcium in months.

What exactly are you dosing and how much?

I think this point is greatly exaggerated by many, but it is why I stated that he should adjust as needed.

All types of calcification use a relatively fixed ratio of 2.8 dKH to 18-20 ppm calcium. Even when that ratio is taking place, folks often easily detect the alk decline and cannot easily detect the calcium decline with noisy and imprecise hobby kits. Some then falsely conclude calcium is "stable" and alk is declining. An alk decline of 0.2 dKH per day will not be accompanied by a detectable calcium decline.

There are a very few other processes that add or consume alkalinity and not calcium, and in a tank with very low demand for both by calcification, these can be significant.

The ONLY significant processes that impact the alk and calcium consumption ratios are:

1. Water changes with mixes that do not match the tank. The excessive calcium relative to alkalinity in many mixes leads some folks to incorrectly think only alk is being used.

2. Rising nitrate depletes alkalinity. Alk decliens by 2.3 dKH for each 50 ppm of nitrate increae.

3. Declining nitrate or dosing nitrate adds alkalintiy at the same rate: 2.3 dKh per 50 ppm nitrate.

4. Sulfur denitrators deplete alkalinity.

5. Top off water can contain alk or calcium or both, if it is not purified adequately.

6. Many additives can contain some alk or calcium, and reefers are not always aware of this (often because the manufacturer is not aware or chooses to ignore the fact). Seachem Reef Calcium adds alkalinity for example, but Seachem ignores this issue despite being told about it. Brightwell pH + is purely a high pH alk additive, despite them claiming it does not add alkalinity.

7. test errors are often attributed to unbalanced demand.

I do not know of any other significant processes that impact alk or calcium in reef tanks, so if you have an unbalanced demand, one or more of these is likely the cause.

This has more details on all of these processes:

When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com

 

[Mrzak92]

Correct, they are not designed for 1:1 dosing.

Balanced dosing is about 18-20 ppm calcium for each 2.8 dKH of alkalinity

For calcium: Liquid supplement: 1ml will raise the Ca level of 100 liters (25 gal) by 2ppm.
For alkalinity: Liquid supplement: 1ml will raise the Alk level of 100 liters (25 gal) by 0.036 meq/l (0.1dKH)

In a 25 gallon tank,

28 mL gives 2.8 dKH
9.5 mL will give 19 ppm calcium

Thus I would dose alkalinity as needed, and then dose 9.5/28 = 34% as much of the calcium part. Adjust the calcium every so often if it seems to be rising or falling too much.

Thank you for your response Randy appreciate it.

In my case where i have 42 gallon (160 litre) would this mean to raise my alk from 8 to 9DKH i would dose 16ml of Foundation B and dose approx 5 ml of foundation A to keep the balance. 1:3 ratio would you agree?

sorry to ask you all these question you may have answered this is my first reef tank but i am not really good at chemistry and have been reading a lot of forums recently and never found much information on red sea liquid dosing.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you for your response Randy appreciate it.

In my case where i have 42 gallon (160 litre) would this mean to raise my alk from 8 to 9DKH i would dose 16ml of Foundation B and dose approx 5 ml of foundation A to keep the balance. 1:3 ratio would you agree?

sorry to ask you all these question you may have answered this is my first reef tank but i am not really good at chemistry and have been reading a lot of forums recently and never found much information on red sea liquid dosing.

Yes.

 

[Mrzak92]

Yes. Thank you for the information and confirming this. much appropriated.

 

[ariellemermaid]

What exactly are you dosing and how much?

I think this point is greatly exaggerated by many, but it is why I stated that he should adjust as needed.

All types of calcification use a relatively fixed ratio of 2.8 dKH to 18-20 ppm calcium. Even when that ratio is taking place, folks often easily detect the alk decline and cannot easily detect the calcium decline with noisy and imprecise hobby kits. Some then falsely conclude calcium is "stable" and alk is declining. An alk decline of 0.2 dKH per day will not be accompanied by a detectable calcium decline.

There are a very few other processes that add or consume alkalinity and not calcium, and in a tank with very low demand for both by calcification, these can be significant.

The ONLY significant processes that impact the alk and calcium consumption ratios are:

1. Water changes with mixes that do not match the tank. The excessive calcium relative to alkalinity in many mixes leads some folks to incorrectly think only alk is being used.

2. Rising nitrate depletes alkalinity. Alk decliens by 2.3 dKH for each 50 ppm of nitrate increae.

3. Declining nitrate or dosing nitrate adds alkalintiy at the same rate: 2.3 dKh per 50 ppm nitrate.

4. Sulfur denitrators deplete alkalinity.

5. Top off water can contain alk or calcium or both, if it is not purified adequately.

6. Many additives can contain some alk or calcium, and reefers are not always aware of this (often because the manufacturer is not aware or chooses to ignore the fact). Seachem Reef Calcium adds alkalinity for example, but Seachem ignores this issue despite being told about it. Brightwell pH + is purely a high pH alk additive, despite them claiming it does not add alkalinity.

7. test errors are often attributed to unbalanced demand.

I do not know of any other significant processes that impact alk or calcium in reef tanks, so if you have an unbalanced demand, one or more of these is likely the cause.

This has more details on all of these processes:

When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com

Thanks that’s super helpful! I have been a little puzzled by what’s going on with it. The tank I’m talking about is a 20g long term coral/invert reef I use for QT. I monitor Alk and Ca both with a Trident and Red Sea kit which tend to agree.

However I think all of the things you mentioned are present. Nitrates run on the higher side (20’s, no sump or great option for export), and I try to do weekly water changes that amount to about 30% so salt mix could be a factor. Even if my testing isn’t accurate it should be consistent and throughout the week I consistently see Alk decrease (balanced by dosing) while Ca remains stable. I’m using Seachem Fusion Alk at the moment. The only time I had significant Ca consumption (and much higher Alk consumption) was when I had a large birdsnest coral (also the only time nitrates have been <5). Otherwise the tank seems to consume Alk without Calcium and this I’ve long felt this is attributable to factors other than coral consumption, but it’s always been a mystery to me.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks that’s super helpful! I have been a little puzzled by what’s going on with it. The tank I’m talking about is a 20g long term coral/invert reef I use for QT. I monitor Alk and Ca both with a Trident and Red Sea kit which tend to agree.

However I think all of the things you mentioned are present. Nitrates run on the higher side (20’s, no sump or great option for export), and I try to do weekly water changes that amount to about 30% so salt mix could be a factor. Even if my testing isn’t accurate it should be consistent and throughout the week I consistently see Alk decrease (balanced by dosing) while Ca remains stable. I’m using Seachem Fusion Alk at the moment. The only time I had significant Ca consumption (and much higher Alk consumption) was when I had a large birdsnest coral (also the only time nitrates have been <5). Otherwise the tank seems to consume Alk without Calcium and this I’ve long felt this is attributable to factors other than coral consumption, but it’s always been a mystery to me.

Glad it was interesting.

FWIW, I know you aren't dosing the calcium part of Reef Fusion, but just in case...

Seachem Reef Fusion is not properly alk/calcium balanced for 1:1 dosing

A recent thread in the chemistry forum from someone who found that calcium increased with this product while maintaining alkalinity and using 1:1 dosing as advised by Seachem provoked me to check it's manufacturer specifications to see if it was a balanced additive. From Seachem's claims about...

www.reef2reef.com

 

[rebels23]

I have been dosing with Red Sea Alk only each day as my Calcium is above 500 ppm due to my salt mix being high (IO Reef Crystals). Based on the above, I should always be dosing Red Sea Alk with Red Sea calcium even though my calcium level is at 500 ppm?