dosing kalk to raise ph

dolphin_swim

New member
I have read Randy's article on raising ph and kalk dosing while checking into countless threads in an attempt to raise the ph on my tank. As I am restricted by space, I started out dosing a hypersaturated solution, i.e. with the slurry, controlled by a dosing pump every 20 mins throughout the day. It worked very well for a week -- corals that had no polyp extension for a long time started to show signs of life again; visible growth on sps happened almost overnight; colors enhanced; fishes swam peacefully without the occasional darting around as before.

After that first week, things start to fall apart as the dkh started to continuously climb. I got worried and tried to adjust the dosage, getting buckets of normal saturated solution into the living room (in a small apartment) in hopes to meet the demand and try to make things stable. I still ended up with a disaster, killing many of my beloved new corals.

Here's the rise and fall of the tank:

ph_kh.jpg

Tissue recessed on all corals, and I do not know whether it is caused by:

1) unstable alkalinity
2) unstable ph
3) unbalanced alk/cal/mag -- cal/mag were 440-450/1250-1350 for some time; today these dropped to 380/1050 (I suspect this dropped after a water change with natural sea water a few days ago)
4) alkalinity too high, nutrients too low -- no3 ~2.5-5 ppm (salifert); po4 3 ppb (Hanna phosphorus ULR). I have read used the reef calculator http://reef.diesyst.com/chemcalc/chemcalc.html which showed that balanced dKH for 450 ppm calcium is 4.45meq/l (12.46 dKH)
5) unstable salinity -- have been dosing at least 15L of kalk solution day to try to reach 8.3 (the number that resulted in happy corals), this dropped the salinity to 1.021, hence the water change which makes it now 1.023
6) something else

I have tried open windows and CO2 scrubber into the skimmer and neither had much effect on raising the pH. Also tried Seachem Reef Buffer yesterday, and as expected, it raised the dKH much more than the pH.

I would really appreciate advice from experts here so I can stop the killing :sad2:
 

Vinny Kreyling

Premium Member
STOP trying to chase PH, it's a waste of time.
Just use your kalk solution water as top off.
Stability is more important in all parameters.
Many tanks run @ a lower PH especially in winter months when homes are tightly closed with no air exchange.
 

dolphin_swim

New member
STOP trying to chase PH, it's a waste of time.
Just use your kalk solution water as top off.
Stability is more important in all parameters.
Many tanks run @ a lower PH especially in winter months when homes are tightly closed with no air exchange.



That's what I have been reading time and time again, and it differs from what I saw when the pH was at 8.3. I have never seen the corals looked so good in the past two years I have had the tank.


Sent from my iPhone using Tapatalk
 

joejvj

Member
May not have been a change in pH value that made your corals improve. It could very well be a change in alkalinity or some other element.

As you say you are limited in space and equipment in your apartment, perhaps a daily 2-part dosing might work better for you than the limewater setup.
 

hkgar

New member
It was NOT the high ph that caused the coral change. I have very happy and growing corals (tank uses 3.2 dKH ALK/day).

PH is the brat of the tank. It is going to do what it wants to do and will be saying screw you while doing it. You CANNOT control it except by removing CO2 which will have about a .02 change
 

dolphin_swim

New member
I have finally found the answer I need in another forum where Randy discusses "œhigh alkalinity what does it really cause".

I have no doubts about the positive effects of the having the higher pH, as discussed in a number of videos on this issue. So in case anyone wants to try it and runs into high alkalinity issues, look for that discussion thread.
 

bertoni

Premium Member
The "balance" part of that calculator doesn't mean much, and the corals will be happy as long as the parameters are in the acceptable ranges, generally 7-11 dKH and 350-500 ppm calcium or so. 11.73 dKH is not high enough to cause problems in most systems, but some tanks show problems much about 8-9 dKH.

That seems to be more common in tanks that measure very low in dissolved nutrients, and get carbon dosing or have some similar dissolved nutrient reduction scheme. The levels you quote probably are outside the danger zone.

pH at 1.021 is low enough that it might cause problems for corals

If you want to increase the pH using Kalk, adding a fan can increase evaporation, allowing more topoff water. If the alkalinity rises, then the tank needs fresher air to increase the pH, which can involve removing a tank cover in addition to opening windows. Also, keep in mind that measurement issues with pH are fairly common.
 

dolphin_swim

New member
The "balance" part of that calculator doesn't mean much, and the corals will be happy as long as the parameters are in the acceptable ranges, generally 7-11 dKH and 350-500 ppm calcium or so. 11.73 dKH is not high enough to cause problems in most systems, but some tanks show problems much about 8-9 dKH.

That seems to be more common in tanks that measure very low in dissolved nutrients, and get carbon dosing or have some similar dissolved nutrient reduction scheme. The levels you quote probably are outside the danger zone.

Thank you, bertoni.

Apart from burnt tips and long term health of the fishes, are there any other problems that one can expect from keeping tanks at a high alkalinity?
 

bertoni

Premium Member
I think the fish should be fine. What fish problems are said to be caused by high alkalinity? Burnt tips on corals are the only likely issue of which I am aware.
 
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