PH Question

[NJ Reefer]

Need a little help here. I did my weekly water change today, about 25% because I am trying to get my nitrates under control. I noticed later looking at the Apex graph that my pH dropped from 8.45 to 7.78 with the water change. About an hour later it was back to 8.12. My pH has consistently ranged from 8.37 to 8.56 over the last few months. The huge swing today really concerns me. Is this my water, salt, etc??

I make my own RO/DI water and use RC salt. I mixed the salt for a little over 24 hours. Temperature didn't change much, and salinity was consistent at 1.026.

Has anyone else experienced this?

 

[chipmunkofdoom2]

Hey NJ, what are your alkalinity, calcium and Mg levels? The alkalinity levels at the very least play a pretty big part in maintaining a stable and high pH. Also, what was the alk and pH of the new water before adding to your tank?

 

[NJ Reefer]

Hi Patrick,

My ph was 7.1 dkH at the time of the water change and 8.2 as of this morning. My alkalinity typically ranges from 7.0 to 8.5 during any given day depending on the time of day and where it is in the dosing schedule. Not sure what the calcium was, although it has been running around 410.

I did not test the parameters of the new water...frankly just too much testing to do on a regular basis. But I will obviously test it need weekend before the next water change.

 

[chipmunkofdoom2]

I agree with you on the testing, I wouldn't bother testing every new batch of water, but it might be worth it if you're experiencing issues with water quality (like you are now). If your salt mix is going bad or you're hitting a spot in the bucket where the homogenity is off, this is really the only way to tell. Otherwise, you mix up a water change, add it to your tank, and then have water quality issues that you can't explain.

You said your pH was 7.1 dKh.. did you mean your alkalinity? pH isn't measured with a unit, unless you break it down into mol/L. Alkalinity is measured in dKh or meq/L. Also, you mention that your alkalinity ranges from 7.0 to 8.5.. IMO that's way too big of a swing for alkalinity in one day. Even if you meant pH, that's still a huge swing.

 

[NJ Reefer]

I did mean Alkalinity (was typing too fast trying to get the door this morning).

My alk does vary that much on a daily basis, which is a bit concerning. If I don't supplement the alk to the extent I am doing, it will drop severely. I dose alk during the night and morning before the lights come on. I do not dose while the lights are on in fear that it will increase the pH beyond the already somewhat high measurement of 8.56.

Do you know of any way to maintain alk without the large fluctuations I am observing?


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[reefin101]

A swing like that is nothing to worry.
It will drop at times. next party or get together watch your pH log. It will drop a decent amount depending on size of house and size of party. But for avg house and avg party you can easily see it drop about .3-.5.

If concerned just open a window to get fresh air in and CO2 out!

 

[NJ Reefer]

Thanks Reefin. What about the alkalinity? Would you be concerned about the daily fluctuation in that?


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[reefin101]

As for Alk, swings from WC's gonna happen especially if its a large percentage and your mix water and tank water are way off. An alk swing of .5 or less would be best

I would either look for a salt that mixes up where you plan to keep tank ALK at:
or keep your tank at what your salt mixes up at
or do smaller percentage WC's where Alk doesn't change so much.

 

[reefin101]

Daily alk swings like you see of 7.0-8.5 is not good!
you really should not have much of if any, you need to get set up some how to automate dosing if you are using that much alk each day.

Bubble magus are great and cheap dosers.
Mine has been rocking for 5 yrs now!
I dose about 300ml of each alk & cal daily

 

[NJ Reefer]

So that's the strange thing. I am using automatic BRS dosers controlled by an Apex for Alk and Calc. I am dosing about 75 ml of Alk over 15 hours, beginning at 9 pm and ending at 11 am. Should I change my schedule?


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[reefin101]

something isn't right?

Are you just seeing brief spikes and troughs? Or is it a gradual incline and decline over hrs?

You sound to be doing it right?

 

[jpsika08]

Check if the probe is working, try using a standard PH test kit instead just to be sure your Apex probe isn't failing or needs re-calibrating.

 

[NJ Reefer]

PH rises steadily when the lights come on at noon. Keeps rising until lights go out at 7:30. Then it's pretty stable over night. It was the deep drop after a water change that made me worried.

The Alk on the other hand fluctuates more dramatically. Up and down about 1.2 dkH. It peaks at 11:00 am when my dosing stops, and is at it's lowest right before the dosing starts at 9:00. Can't tell if it is a series of spikes in between because I only spot test it.


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[reefin101]

That looks fine.
The drop during WC is partly from you breathing heavy adding CO2 to air and your salt mix.

No worries. Just look into salt mix with closer ALK to you tank or tank closer to salt mix

 

[reefin101]

I would just spread your dosing to over 24 hr period, not just lights out so it doesn't change during light hours. Or atleast go a little more into the start and ending hours with dosing. I get what your trying to accomplish by dosing at night, but a gradual pH swing of .4 is fine.

I have pretty much 8.0 in am and 8.4 in eve.

 

[NJ Reefer]

Got it thanks again Reefin. So, I should be less concerned about the pH swing than the Alk fluctuations. I will spread it out like you suggest, but will still watch for more significant pH changes. Only other concern though is that the pH is already reaching 8.56 without dosing during lights on. How much higher can it go and still be safe?


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[reefin101]

I am not sure, but u probably won't go much higher. Most have the opposite problem. It's low 8's to high 7's.

IIt's more consistent and steady fluctuations. So if u go 8.2-8.6 all good over the night and day. Better that than alk fluctuating daily.

For most oH is just what it is. If not over 8.7 or under 7.7 I wouldn't stress

 

[NJ Reefer]

Excellent. I will see how it goes. Thanks for your help.


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[NJ Reefer]

So after much tinkering, it looks like I have my Alk honed in on 9.02-9.24. Much more consistent than before.

The pH is also relatively stable at 8.47-8.63. I'm just a little uncomfortable with the elevated pH. I may add a second airstone to see if the brings it down a bit.


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[reefin101]

lower your alk to like 8.5 and see if pH drops a tad.
Otherwise don't fret it.

Looks good!