Kalkwasser Dosing

[whitt]

I’ve got a 280 gallon system that I’ve recently set up. I’ve now acquired several frags, and have started dosing kalkwasser to bring ph up and bring alkalinity and calcium up. I started out dosing about 5600ml a day to see what happened, and have since upped that dosage to 15,200 ml. Alkalinity and calcium both contribute to decline, but calcium has leveled off at around 360 while alkalinity has dropped to about 7.0 from a 7.9 starting point. I don’t see any signs of precipitation yet, so am confused at what I’m doing wrong. I am dosing with Neptune DOS through a 3 gallon ice cap stirrer. What say you?

 

[Randy Holmes-Farley Verified Community Expert]

15 L os saturated kalkwasser is 1.6 dKH in 289 gallons. How did you make the kalkwasser?

The sand may be precipitating calcium carbonate. How new was it?

 

[whitt]

15 L os saturated kalkwasser is 1.6 dKH in 289 gallons. How did you make the kalkwasser?

The sand may be precipitating calcium carbonate. How new was it?

Thanks for the response. I mixed Brightwell Kalk+2 in the 3 gallon stirrer, and just added enough to make 21 gallons of saturated, so that as it is used up it would stay saturated for a length of time. And the apex turns the stirrer on for 1 minute every hour. Sand was new in bag dry aragonite special grade. Rock is about 60% dry rock and 40% live rock from LFS. I’ve not noticed any clumping sand yet, and have a Melanarus wrasse that seems to have no trouble burrowing the sand at night.

 

[whitt]

Thanks for the response. I mixed Brightwell Kalk+2 in the 3 gallon stirrer, and just added enough to make 21 gallons of saturated, so that as it is used up it would stay saturated for a length of time. And the apex turns the stirrer on for 1 minute every hour. Sand was new in bag dry aragonite special grade. Rock is about 60% dry rock and 40% live rock from LFS. I’ve not noticed any clumping sand yet, and have a Melanarus wrasse that seems to have no trouble burrowing the sand at night.

System was set up in late January for reference.

 

[Randy Holmes-Farley Verified Community Expert]

Just realize that the magneisum in kalk+2 is not useful. It contains very little (less than is present as an impurity in the normal calcium hydroxide I used) and won't dissolve into kalkwasser anyway.

FWIW, kalk stirrers often do not product saturated kalkwasser. i suggest trying to measure the potency. Do you have a conductivity meter that can read 10 mS/cm?

 

[KStatefan]

FWIW, kalk stirrers often do not product saturated kalkwasser. i suggest trying to measure the potency. Do you have a conductivity meter that can read 10 mS/cm?

Is that a linear relationship? ie reading 7.5mS/cm would be 75% saturated

 

[Randy Holmes-Farley Verified Community Expert]

Is that a linear relationship? ie reading 7.5mS/cm would be 75% saturated

Yes.

It does depend on temp a bit. At lower temps, saturation will be higher than at higher temps. At 25 deg C, it is close to 10.3 mS/cm.

 

[whitt]

So while I don’t have a conductivity meter that will read in mS/cm, my tds meter reads about 765 ish, starting with 0 tds water before adding kalkwasser. That reading is at roughly 45 minutes since the last stir.

 

[whitt]

Here’s my parameters over the past few days.