I'm having a bad pH morning

[Armando]

The pH in my tank is reading 7.6 this morning. Yesterday also was 7.6 in the morning. I'm using both an Aquacontroller and a pinpoint to measure it. They seem to be correctly calibrated (I recalibrated yesterday). Can this be right?

 

[jango]

Do you have a good test kit you could try to triple check it with?

 

[Reef55]

Certainly possible. Are you running a calcium reactor? Any refugium?

 

[me2003]

"(I recalibrated yesterday) "
Your calibration solution maybe incorrect. Try measuring the
pH of RO water ~7.0

 

[starrfish]

This is probably a dumb question, but if we know the ph of RO water why bother buying the calibration fluids? I have the hardest time trying to calibrate my ph monitor - up and down, up and down....urgh....

 

[Armando]

I just tested with a Salifert pH test kit. The color is somewhat between the 7.4 color and 7.7 color. So I'd say the 7.6 reading seems correct.

I also tested my second tank using the same test kits, and tested other params. here is what I got:

           tank1    tank2
         ----------------
pH           7.6     7.8
KH           4.8     9.0
Calcium      440     500

The alk on the tank1 is extremely low, along with the pH

Ca was always high on tank2.

 

[Chris A.]

If you bring your alk up the ph will also come up(it will blow off excess Co2)

 

[nunofs]

Try measuring the pH of RO water ~7.0

Sorry, but that's a bit misleading... RODI water has an undetermined pH because it doesn't have any dissolved solids, so the pH will vary depending on other factors such as CO2 in the ambient air. It's definitely not a good calibration fluid.

RO water is also not a good comparison because you never know exactly what's in it (it will have a varying degree of dissolved solids, depending on your membrane and the quality of your tap water).

Nuno

 

[~Flighty~]

Sorry, but that's a bit misleading... RODI water has an undetermined pH because it doesn't have any dissolved solids, so the pH will vary depending on other factors such as CO2 in the ambient air. It's definitely not a good calibration fluid.

RO water is also not a good comparison because you never know exactly what's in it (it will have a varying degree of dissolved solids, depending on your membrane and the quality of your tap water).

Nuno

Seconding these statements. Alc will be zero, but ph measures the ratio of the acid stuff to the base stuff in the water, so a teeny amount of anything will throw the ph of rodi way off. Alcalinity measures how much of the "stuff" is in there. Another way to think of it is if you had a cup of tank water that you measure ph and alc on, then you added a cup of rodi to it. The new reading would be the same for ph (you didn't change the ratio) and half for alcalinity (you diluted the "stuff")

Did that make any sense?

 

[Armando]

that's true Chris. it looks like a lot of adjustment to be made with baking soda/etc. i'm mixing water and will change 20% before I make any adjustment. not that a water change was overdue, i changed it in less than 2 weeks.

 

[me2003]

"Sorry, but that's a bit misleading... RODI water has an undetermined "
I agree that it should not be used for calibrations. It lowers the concentration
of many ions and for me has measured ~7.0. It just a quick check to see if it has shifted. You need to use multiple calibration fluids to establish a line. 4.0,7.0 and
10.0 ph solutions are needed.

 

[~Flighty~]

"Sorry, but that's a bit misleading... RODI water has an undetermined "
I agree that it should not be used for calibrations. It lowers the concentration
of many ions and for me has measured ~7.0. It just a quick check to see if it has shifted. You need to use multiple calibration fluids to establish a line. 4.0,7.0 and
10.0 ph solutions are needed.

It lowers the concentration, but the ph measures the ratio, not the concentration.

 

[NateHanson]

I'll second Chris' suggestion. High Alk is needed to keep pH up, and also to buffer the tank against large pH swings.

Nate

 

[Chuck Spyropulos]

Armando, is this a sudden drop, or has the pH been dropping a little over an extended period ? If pH has been dropping, then it is probably a low Alkalinity problem. If it is a sudden pH drop then the questions are: what has changed? Windows opened vs normally closed or vice versa? Excess C02 in your room? Clogged Calcium reactor? Clogged Kalkreactor? Circulation decrease?

 

[Armando]

Chuck i'm not sure, but the alk is definitely low.

I made a 20% water change during the weekend and this morning I made an involuntary (AKA FLOOD) 10% water change. I have to check the alk again, hope it's back up.

 

[Armando]

Armando, is this a sudden drop, or has the pH been dropping a little over an extended period ?

Here is the wide fluctuation. I really like this Aquacontroller, even when it tells me i suck as a reefer

 

[~Flighty~]

wow, what's the deal with the temp swing? Is that from your lights?

 

[Armando]

Yes, when the lights are on the temp slowly climbs to 82ish, even with the chiller.

 

[Reef55]

Yikes, that is a lot higher of a swing than mine...

Here is mine... the larger than normal temp swing on the evening of the 13th was when I had my growout tank light on while working on it (it normally isn't on when the main tank lights are).

Can you post with the photoperiod of your lights added in? If changing your light pattern can't help this, you might be in the market for a chiller.

 

[Armando]

I have a chiller Problem is that I run a *lot* of lights. More specifically - 7x 250HQIs + 3 x 150HQIs.

The photoperiod is 1pm-8pm