How to lower PH

[opinicon2]

I setup my 90 gallon reef tank about a year ago. My PH has always been low around 7.5 to 7.8.

I read a about adding kalwasser so I bought a gravity drip bottle and added some last night...not much 1 tsp in a gallon of RO water.

Well today my PH was still hovering about 7.6 so i decided to add some PH UP. I added 1 tsp which is what I normally add since I have trouble getting my PH any higher then 7.8.

Well 4 hours after adding the PH UP my PH is shooting thru the roof.

It's at 10.0.

I did a 20 gallon water change hoping this would lower the PH but it hasn't. I turned my light off since the PH seems to go down when the lights are off.

What else can I do to lower my PH before my corals die. Or will my corals be okay for a few days until the PH lowers by itself.

Any help would be apprecated

[Sisterlimonpot]

Some questions:

How do you test PH?

What type of substrate do you have? Sand?

What type of salt do you use and how often do you conduct water changes?

What do you have as far as livestock in your tank?

[opinicon2]

I have a pinpoint PH tester. I have a 3 inch sandbed and about 7 fish. I buy already prepared saltwater from my LFS so I'm not sure what type of salt they use.

Any suggestions for lowering my PH. I read vinegar will lower it but I can't find any measurements on how much to add.

I do a 10% water change every other week. I did a 20% water change when I noticed my PH at 8.6. But it continues to rise.

I removed my favorite corals hoping to save them.

[ritter6788]

Are you still using the kalk drip?

[Sisterlimonpot]

I have a pinpoint PH tester.

That’s exactly what I was concerned about, When was the last time you calibrated your PH probe?

If the sand is aragonite then it should be a natural buffer, and to top it off if you have corals in there and they were thriving then I would suspect a faulty reading, before using buffer did you verify with another test to make sure that the PH was off?

[opinicon2]

I plan on only using the kalk drip when my PH goes back down to 7.x. I thnk I should have only used 1/4 tsp ph up.

I had been using a whole tsp because I was trying to get my PH up and it wasn't budging.

Originally Posted by ritter6788

Are you still using the kalk drip?

[opinicon2]

Originally Posted by Sisterlimonpot

That’s exactly what I was concerned about, When was the last time you calibrated your PH probe?

If the sand is aragonite then it should be a natural buffer, and to top it off if you have corals in there and they were thriving then I would suspect a faulty reading, before using buffer did you verify with another test to make sure that the PH was off?

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I'm suspecting the probe might be bad because I placed it in my 10g planted tank and it came back with a ph of 10. I then placed it in some R/O water and again 10.

I calibrated it about 2 months ago. I ran out of calibration fluid so I need to order some more.

I used a test kit to test my PH and the kit only goes to 8.6 so I know for sure
my ph is at least 8.6.

Can I use vinegar to lower my PH? Does anyone know how much?

[opinicon2]

I added some seltzer water and that seems to be doing the trick.