Acetic Acid question?

[cardinalfanrc]

After reading Randy's articles on PH/alk/Ca and Craig Gingmans's article on expanding the use of kalkwasser I am considering using white vinegar to lover my ph.
I have a 75 gallon reef and use a kalkwasser reactor to maintain my calcium and alkalinity. I usually drip at a rate of 150cc/hr overnight when the lights are off. Over the last several months my ph has been slowly rising. My current numbers are ph 5.0 (pinpoint monitor)day (4.5 at night) with Ca 390 and alk 3.2. I previously had a minor tank crash from high ph (before I had a ph monitor and closely followed my ph). I'm now considering adding white vinegar to lower my ph. Is this a good idea and if so how should I add it? My kalkwasser reactor draws RO/DI from a 20 gallon trash can resevoir. Can I add the vinegar to the RO/DI resevoir? I'm worried that it will separate out from the water and not be evenly distributed. Any help is appreciated. Thanks.

 

[randy holmes-farley]

Yes, you can add it directly the the reservoir. It will very quickly become totally mixed into the water and will never seperate back out.

How high was the pH getting at its peak?

 

[cardinalfanrc]

Randy - Thanks for the quick reply. The Ph now peaks at 5.0. Since all of my fish and corals look great I'm not too concerned that 5.0 is too high. However, it has been slowly rising and I'm anticipating that it will keep rising. I'm pretty sure that a previous gradual decline in tank health about six months ago and before I had a Ph probe, was due to a slow rise in my Ph. Please le me know if an anticipated continued rise in Ph makes sense. Thanks for your help.

 

[randy holmes-farley]

Where is the pH 5.0?

 

[cardinalfanrc]

The Ph is 5.0 during the day and approximately 4.5 with lights out. It is measured in the sump with a pinpoint ph meter, recently calibrated. The tank is a 75 gallon reef with a relatively small bio load. I have a 20 gallon sump and ten gallon refugion on reverse light cycle. I'm currently running my kalkwasser reactor only at night. Thanks for the help.

 

[randy holmes-farley]

I'm not sure what you are talking about. The pH can't be 4.5 in a reef aquarium. All of the rocks would dissolve.

 

[cardinalfanrc]

Sorry, that was a typo. I meant that the Ph was 8.4 in the morning and 8.5 in the evening. Although now the Ph is close to 8.6 by the late evening after the lights have been on all day. I have stopped dripping kalk for the last 2 days. Over this time period I have dripped in 4 gallons of RO/DI with 6 ml of white vinegar per gallon. The Ph has essentially remained unchanged. I assume that I simply have not added enough acetic acid to meet the lack of CO2. Am I still on the right track? Thanks.

 

[randy holmes-farley]

It surprises me that the pH didn't drop from the stopped limewater alone. If I stop my limewater for 24 h, the pH drops.

If you are sure that you ph reading is correct, then more vinegar will help, yes.