PH and Kalkwasser?

[schigara]

I never payed much attention to my PH until now that I am keeping 11 SPS frags/small colonies and 3 LPS specimens. I have been very careful at keeping my CA and ALK in line. I average 450 Ca and 10dkh Alk(Salifert).

I bought a Pinpoint Ph meter a few days ago and calibrated it with the Pinpoint 7.0 and 10.0 solutions.

I knew from my Salifert kit my PH was always on the low side but never really knew exactly what was going on until now.

I have been 2 part dosing with Brightwell Aquatics and have been keeping Ca at 440-460 and Alk at 9.6-10.2 dkh.

I would dose 20ml of each part morning and night(40ml total of each per day). In the morning, before lights came on and before dosing, Ph was 7.98 and at the end of the day right before Halides turned off, PH was 8.15

Tank is 75g and sump is 55g. Water crashes 5 inches in overflow and is noisy and I have an Octopus NW200 skimmer and the surface of the DT is rippled very hard by the two Seio 1500 pumps which alternate on a Tsunami wavemaker. Aeration is good! My 55g sump is sectioned with 1/3rd as refugium with a nice spinning ball of Chaeto and the refugium is on a reverse light cycle.

Last night I dripped Kalk for the first time. I am using Brightwell Kalk+2. I mixed 2 teaspoons of Kalk in a 2gallon container using RO/DI and dripped at a rate of about 1 drop per second. I let the container of Kalk settle for 6 hours before dripping. When I got up this morning, the Ph was at 8.01 where before would be 7.98.

Today I remixed the Kalk container at 2 teaspoons per gallon(4tsp total) and started dripping at 1 drop per second and also did not dose with the 2 part. It is now 1:40 in the morning and the Ph is reading 8.16 steadily.

Should I just drip Kalk at night and stop Dosing 2 part so long as the Ca, Alk, Mg and PH hold steady? Oh, my Magnesium has been reading 1380-1400 all along while dosing Brightwells 2 part.

Will this Kalk drip hold the Ca and Alk?

Brightwell Kalk+2 says it also contains Magnesium and Strontium. Everything I have read about Kalwasser says that things like Magnesium, will fall out of solution in Kalkwasser. Please explain.

Sorry for the long winded post but just trying to cover most of the bases.

Any info, insight or just basic advice is greatly appreciated.

 

[Amphiprion]

You can drip the kalkwasser 24 hours per day, so long as the pH shift isn't gigantic (no more than 2 or so units).

They do indeed precipitate in a solution of kalkwasser. All you really have is limewater with a lot of impurities in it--only to have them precipitate and become useless. Well, at least magnesium, for the most part.

 

[schigara]

This morning the PH was still at 8.15 and the Alk is still about 10.4 dkh. It had gone through a little more than a gallon of limewater.

I stopped the drip to see whay would happen to the PH since the halides are on and in 4 hours with lights on, PH has dropped to 8.04 so it seems that running the drip 24/7 should hold the PH steady.

You can drip the kalkwasser 24 hours per day, so long as the pH shift isn't gigantic (no more than 2 or so units).

 

[Fishieness]

yes. many people do drip it at night to help keep pH swings to a minimum. However, your pH swing really isnt bad at all, and the amount that the kalk is preventing really wouldnt even make a difference.
and the percipitate is calcium carbonate (CaCO3) which is what happens when atmospheric CO2 is present in the water. I've heard of some people adding vinegar to help this. I've never done this, but from a chemist's viewpoint, it makes sense to me as to why it would work.
good luck with the new method. Me personally, I was never able to keep up with ALK when dosing kalk, but i had a pretty high demand for a pretty small tank.

 

[Mr.Firemouth]

Shigara, please stop watching your pH. It is fine.
The 3 crucial elements to be concerned with is Calcium, Alkalinity, and Magnesium.

You must understand that the above 3 work in unison with each other always trying to be in some sort of equilibrium. PH on the other hand is always in flux. PH will be changing from day to day because of things such as carbonic acids, oxygen levels(redox), feedings, photoperiod(lights), etc.

Your main concern is maintaining the 3 elements I have mentioned and just let pH fall where it may. As long as your salinity is 1.024-26 and the Ca/Alk/Mg are at desired levels you are fine.

Weekly water changes help to keep levels in the desired range and maintain excellent water quality.(assuming that the source water is RO/DI with 0 TDS)

Also remember to only dose products as they are needed. This will eliminate the chance of accidental overdosing. Anytime you have a serious issue with a spike in your water parameters a large water change will help to stabilize the situation.

The goal to successful reefkeeping is consistency. The more stable the system is the better long term success you will have.

HTH, Rich

 

[Amphiprion]

Shigara, please stop watching your pH. It is fine.

You must understand that the above 3 work in unison with each other always trying to be in some sort of equilibrium. PH on the other hand is always in flux. PH will be changing from day to day because of things such as carbonic acids, oxygen levels(redox), feedings, photoperiod(lights), etc.

HTH, Rich

I can only partially agree with this. While the actual value for pH is relatively unimportant so long as it falls within the general recommended range, if schigara is using kalkwasser, monitoring pH initially is crucial. Until he is able to get an adequate daily amount set without impacting pH too much, it would be wise to keep an eye on the pH. That being said, anywhere from 7.8-8.5 is considered ok, as long as the kalkwasser doesn't cause too much drift. I do agree, however, that trying to keep it on a specific value is difficult and unnecessary--with the potential to cause other problems.

BTW, oxygen has little to no effect on pH. Of O2 and CO2, the presence or obscurity of CO2 (and organic acids) will be the major factor deciding the flux of pH. There is merely a correlation between the two due to photosynthesis (or in the case of aeration, the gasing of of excess CO2 to the atmosphere).

 

[schigara]

Firemouth & Amphirion,

I agree with both of on not watching the PH and trying to chase the PH with Kalk. I always have to try and see for myself, ya know. Just like 2 part dosing, the Kalk only has a temporary effect on PH. I do however like how well it maintains calcium and alk but my tank isn't consuming enough yet to bother with the hassle of Kalk, so my experiment with Kalk has ended for now.

I am going back to dosing 40ml of Brightwell 2 part as it maintains the Ca and Alk just nicely.

My water params have been:

450-460 Ca
9.6-10.2 Dkh
1380-1400 Mag

I tried something else which worked much better yesterday and it explains the somewhat lowish PH. I opened the windows in the house and the PH slowly rose to 8.2 and stayed at 8.15 overnight.