Kalkwasser issues

[Jizu Puentes]

I currently dose kalkwasser via a dosing pump from a 20 gallon still reservoir. Once the level drops to 5 gallons remaining, I add 30 teaspoons and pump in 15 gallons of RODI. I wait an hour then plug the dosing pump back in and normal dosing resumes. My system is around 300 gallons and I do 30 gallon water changes biweekly using red sea salt. These have been my parameter readings while dosing 61 ml/hr of kalkwasser.
8/18 CA 470 KH 8.1 Nitrates 5
8/25 CA 470 KH 8.1 Nitrates 5
9/14 Ca 480 KH 7.8 Nitrates 5
10/1 CA 470 KH 7.8 Nitrates 5
10/7 CA 460 KH 7.8 Nitrates 5
I wanted to raise my KH to around 8-8.2 so I raised my hourly dose from 61 to 63. Also during this time the weather got cooler and windows were left open boosting my ph from a norm of 8.1 to 8.4. Here is my reading from today, 24 hours after a wc.
10/31 CA 420 KH 6.6 Nitrates 5
Why would I be seeing such a dramatic drop? To correct this should I dose alk back up to at least 8 and up the kalk dosage?

 

[theMeat]

Long my term Kalk dosing can sometimes lead to low alk issues.
Check magnesium level.
Would also say that 3 teaspoons in 15 gallons is rather weak

 

[Randy Holmes-Farley]

The increased pH would increase demand both by corals and from abiotic precipitation, hence the alk declined.

At least, that is a possible reason why.

 

[cmcoker]

Rise in pH can lead to increased demand for alkalinity. I know I have seen Randy mention that numerous times.

Probably easier to use baking soda to bring your alk where you want it and use kalk to maintain from there.

You can use this calculator to determine how much of either to dose. Just remember that kalk needs to be dripped in slowly, in a high flow area.

http://reef.diesyst.com/chemcalc/chemcalc.html

Edit - haha guess I should have refreshed the page before replying.

 

[Jizu Puentes]

Long my term Kalk dosing can sometimes lead to low alk issues.
Check magnesium level.
Would also say that 3 teaspoons in 15 gallons is rather weak

I add 30 teaspoons. 2 teaspoons per gallon

 

[Jizu Puentes]

Rise in pH can lead to increased demand for alkalinity. I know I have seen Randy mention that numerous times.

Probably easier to use baking soda to bring your alk where you want it and use kalk to maintain from there.

You can use this calculator to determine how much of either to dose. Just remember that kalk needs to be dripped in slowly, in a high flow area.

http://reef.diesyst.com/chemcalc/chemcalc.html

Edit - haha guess I should have refreshed the page before replying.

I've already got some oceans blend alk so I'll use that to raise the level to at least 8. I'll setup a slow drip into my sump tonight. Thanks for the link!

 

[theMeat]

Oh, I’m just a bang wiz tonight

 

[Jizu Puentes]

Oh, thought you said 3

Here’s a calculator to figure how much baking soda. I use Kalk And have to do this every few months.

http://reef.diesyst.com/chemcalc/chemcalc.html

Thanks!

 

[Jizu Puentes]

Does the way I mix my new batch sound adequate? I'm not sure if the way I mix it could mess with the saturation. I pump in the new water and it stirs up the slurry on the bottom as well as adds a slight amount of aeration from the surface breakage. I let it all settle for an hour before reconnecting the dosing pump

 

[Jizu Puentes]

Also according to the calculator I need to add 321 ml of the oceans blend. How long of a time period should I make the drip last?

 

[Jizu Puentes]

Oh, I’m just a bang wiz tonight

I read that as Wiz Bang and had BFG thoughts haha (hopefully you know what that is)

 

[theMeat]

Lol,
Would wait more than an hour for slurry to settle. Usually takes my ato reservoir 6-8 hours to settle out.
Also, Kalk looses it effects after some time. Mix a few days worth at a time, a week the most. That’s with a cover on reservoir, Goes bad/useless much faster if exposed to air/without lid

Not sure how much ocean blend, but no more than one dkh per day would be best,

and probably can’t/shouldn’t mix ocean blend with Kalk in same reservoir, as you can’t do that with baking soda, but not sure

 

[Jizu Puentes]

Lol,
Would wait more than an hour for slurry to settle. Usually takes my ato reservoir 6-8 hours to settle out.
Also, Kalk looses it effects after some time. Mix a few days worth at a time, a week the most. That’s with a cover on reservoir, Goes bad/useless much faster if exposed to air/without lid

Not sure how much ocean blend, but no more than one dkh per day would be best,

and probably can’t/shouldn’t mix ocean blend with Kalk in same reservoir, as you can’t do that with baking soda, but not sure

My solution is always clear after an hour.
My 20 gallon reservoir has a tight fitting lid and lasts me 30 days. It's a blacked out 30 gallon tank filled with 20 gallons of kalkwasser.
I'm not planning to mix the oceans blend with kalk, just drip it separately

 

[SteadyC]

Does the way I mix my new batch sound adequate? I'm not sure if the way I mix it could mess with the saturation. I pump in the new water and it stirs up the slurry on the bottom as well as adds a slight amount of aeration from the surface breakage. I let it all settle for an hour before reconnecting the dosing pump

1) I have been using Kalk for a long time, and the one thing I can share is that in the summer here (when doors and windows are open) I have to add soda ash to keep alk mantained (since house co2 drops and there isn’t enough to combine with the hydroxide in kalk to maintain alk alone.). Soda ash is my choice of supplement for alk, as it is bicarbonate and has a better upward impact on PH. So, just wanted to let you know that what you are seeing is normal, when alk dropped, for two reasons 1) corals uptaking more as ph increases, and 2) because you opened windows which dropped the co2 available to combine with hydroxide to make carbonate and bicarbonate (alk).

2) I discard the bottom super saturated solution when I make a new mixture of kalk, rather than remixing with that. You are already at saturation limit by adding 30 teaspoons to 15 gallons. By adding a saturated kalk mixture to the super saturated solution at the bottom, you are wasting kalk. I hate throwing out the bottom gallon, but I know each batch I make is an exact amount of kalk saturation. 2 teaspoons per gallon is the max saturation of kalk. So each time you are mixing kalk, you are adding some that cannot saturate, and why I say you are wasting kalk.

 

[Randy Holmes-Farley]

Let me clarify. You might have needed sodium carbonate to boost alk for several reasons, but not from lack of CO2. The alk delivered does not depend on CO2.

 

[Jizu Puentes]

1) I have been using Kalk for a long time, and the one thing I can share is that in the summer here (when doors and windows are open) I have to add soda ash to keep alk mantained (since house co2 drops and there isn’t enough to combine with the hydroxide in kalk to maintain alk alone.). Soda ash is my choice of supplement for alk, as it is bicarbonate and has a better upward impact on PH. So, just wanted to let you know that what you are seeing is normal, when alk dropped, for two reasons 1) corals uptaking more as ph increases, and 2) because you opened windows which dropped the co2 available to combine with hydroxide to make carbonate and bicarbonate (alk).

2) I discard the bottom super saturated solution when I make a new mixture of kalk, rather than remixing with that. You are already at saturation limit by adding 30 teaspoons to 15 gallons. By adding a saturated kalk mixture to the super saturated solution at the bottom, you are wasting kalk. I hate throwing out the bottom gallon, but I know each batch I make is an exact amount of kalk saturation. 2 teaspoons per gallon is the max saturation of kalk. So each time you are mixing kalk, you are adding some that cannot saturate, and why I say you are wasting kalk.

1.Thanks for that.
2. At the time of mixing I have 5 gallons of saturate solution remaining, I dump the 30 teaspoons on top of that then pump in 15 gallons. You are saying the bottom 5 gallons is wasted?

 

[Jizu Puentes]

Let me clarify. You might have needed sodium carbonate to boost alk for several reasons, but not from lack of CO2. The alk delivered does not depend on CO2.

What are possible reasons?

 

[SteadyC]

Let me clarify. You might have needed sodium carbonate to boost alk for several reasons, but not from lack of CO2. The alk delivered does not depend on CO2.

Alk doesn’t, but the kalk needs co2 to bind with to make alk. Hydroxide + co2 makes carbonate and bicarbonate. Without co2 to mix with, kalk can’t make bicarbonate (alk).

 

[dgrigor02]

Been running kalkwasser using the resevoir method on my show tank for close to 15 years. The 1 concern with your process that I have is mixing every 30days. Target a 10-14 day supply. The potency may be going down the further out beyond 14 days that you go. Best would be to test it with a conductivity meter to see what the potency loss is at 30days if you really wanted to know.

Don't forget when using the resevoir method that can boost by adding some vinegar to get up to 30% more alk delivered. But again, best not to go beyond the 10-14 day interval.

When I need to make alk adjustments, I will do a kalk slurry ( assuming it won't spike pH too much ). I usually avoid carbonate/bicarbonate additives for alk adjustments becuase that throws off my ca levels and I really try to avoid adding chlorides when ever possible becuase I do near zero water changes.

For me, my tank is most vulnerable in the summer time. Close up the house for A/C. Evap goes down, more co2 because windows are shut, pH starts to fall. When pH falls alk consumption drops so I have to be very careful that alk levels dont get too high. In winter when the air is dryer due to running furnace, my tank evap goes up, co2 levels aren't as high becuase all the fresh air the furnace pulls in compared to A/C running, pH goes up, alk usage goes up and is a non issue.

 

[Randy Holmes-Farley]

Alk doesn’t, but the kalk needs co2 to bind with to make alk. Hydroxide + co2 makes carbonate and bicarbonate. Without co2 to mix with, kalk can’t make bicarbonate (alk).

Yes, but it ALWAYS does. There is never any important amount of free hydroxide in the water.

The added hydroxide immediately combines with H2CO3 to form bicarbonate and with bicarbonate to form carbonate to form (and boric acid to form borate).

Unless the pH is too high, there is no concern about free hydroxide. Even at pH 9, the free hydroxide is only 0.01 meq/L or 0.03 dKH.