Low PH with kalk reactor

[StarF]

Hi

I hope someone can help me with this problem.

Before i ran with a kalk reactor, i was using the "balling" method, i have always had a "low" ph in my aquarium, with balling it was around 7.8-7.9.

a month ago i got a kalk reactor, with co2 and everything. Hooked it up, and life was much easier.

How ever today i noticed that my ph was around 7.7

ca: 420
kh 8.3

this was done at around 13.00

at around 20.00 i made another ph test, and it showed 7.6

Is this a problem?

i have lost 2 acropora´s over the last few weeks, they just suddenly shifted all their skin, dont know if its due to the ph?

and what can i do to raise it? i have tryed using baking soda, thats ben in the oven at 200 degrees for a few hours, this dident raise my ph at all..

 

[Randy Holmes-Farley]

So you mean a calcium carbonate/carbon dioxide reactor that uses tank water? Those reactors do typically lower tank pH a bit. More tank aeration with fresh air, using limewater, and possibly running leaner on the CO2 can help raise the pH. This has more:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

FWIW, many people use the term kalk reactor to refer to a Nilsen reactor that uses calcium hydroxide in fresh water to deliver limewater to the tank.

 

[StarF]

hi tnx for your answer..

yes i meant a calcium reactor. I already have co2 turned as much down as i can. It gives a buble every 1-1½ seccond. when its turned on.

would moving the air intake from the skimmer, to outside of the sump do anything to the PH ?

is my ph in any case harmfull to corals?

 

[Randy Holmes-Farley]

pH 7.6 (if accurate) is going to slow calcification substantially. The article linked has some aeration tests you can do to see if simple aeration ill help, or if you need fresher air.

 

[StarF]

just read it, it was a good read, and def got a few thigns i wanna try out. tnx.

 

[Randy Holmes-Farley]

You're welcome.

Good luck.

 

[StarF]

Ok i tryed a few things:

First i made it so the skimmer get´s fresh air
i tryed to raise my kh top 10.

still i cant get my ph up.. its usaly around the 7,6 - 7,7 range.

and i am experiencing a few corals that is starting to lose their skin.. so if some one knows how i can raise it, get it stable.. please let me know.

 

[Randy Holmes-Farley]

Aside from fresh air, limewater is really the only other effective option for dealing with elevated carbon dioxide.

 

[StarF]

ok tnx, i will try and see if i can find that, and if that helps.

 

[StarF]

still a bit in doubt if the ph can be the source of my coral problems or if that is something else.

 

[Randy Holmes-Farley]

At pH 7.6 it could be. But there may be other issues too.

 

[StarF]

ok tnx.. just seems odd, i am having a hard time to raise ph... is it possible to get ph buffers, that dosent affect kh ?

 

[David Grigor]

The root cause is elevated CO2 levels.

PH buffers will not solve this will only screw with your water parameters even more.

Many people that use CA reactors combine it with using Kalkwasser in topoff for the exact reasons you describe.

 

[Randy Holmes-Farley]

is it possible to get ph buffers, that dosent affect kh ?

No, there is no additive of any kind that can raise pH and not supply alkalinity. Limewater has the biggest possible pH rise per unit of alkalinity added, and it does not boost alkalinity relative to calcium.

 

[StarF]

will Calciumhydroxid raise ph along with ca ?

 

[Randy Holmes-Farley]

Yes, calcium hydroxide (as in limewater) raises pH, calcium, and alkalinity. But as you increase the pH, the demand for calcium and alkalinity in the tank usually rises, so you may not notice a boost in calcium or alkalinity when using it.

 

[StarF]

tnx gonna try that then, any idea on how fast it rises ph ? i have around 1700L of water, but i dont wanna mess up my ca/kh to much, so will the best aproach be to turn off the co2, and let ca/kh drop a bit before dosing or?

 

[Randy Holmes-Farley]

If you add 1.25% of the water volume of the tank as saturated limewater, it will boost pH instantly by about 0.6 pH units. Spread that out over time and the boost is much less, as it allows the tank to pull in CO2 from the air.

 

[StarF]

tnx for your help, just bougt some Rowa Kalk - Kalkwasser Mix, i think its the same as Limewater, gonna give it a go

 

[Randy Holmes-Farley]

Yes, that sounds good.

Good luck.