Injecting Co2, pH is all over the place....need help

[Atl300zx]

so i started injecting CO2 yesterday. I have the following equipment:

Milwaukee CO2 Regulator w/ Solenoid Diaphragm Valve & Bubble counter
Aqua Medic CO2 Reactor 1000
Milwaukee SMS122 pH Controller

Here is my problem:

Before i started injecting CO2, my pH was 7.2.

Then i set the pH controller to 6.2 and turned on the co2. I set it the regulator for about 8 bubbles/second. Everything seemed fine until the solenoid kicked in to turn off the flow, when the pH went back up and the solenoid opened, no bubbles were coming out so the pH would jump back up into the 7.0 range. I realized this and turn up the regulator to increase flow. The same thing happened again, but this time overnight. when i woke up this morning, no co2 flow and the tank was at 8.0 pH. I dont know how it got that high. So i turned the co2 up again and went to work. Why is this happening? Am i doing something wrong? I need some help b4 i kill all my fish.

Thanks,

Jimmy

 

[dapellegrini]

Jimmy - very common problem. Just increase the pressure with the big black knob a bit to put some more pressure behind your needle valve and you should be good to go. I have brought mine up to 35psi on the low pressure side in the past, but it now seems to behave appropriately at around 20psi.

 

[Atl300zx]

if i put that much pressure, the bubble counter water will go thru the tube....do i need to raise it up to 10 psi, then control it with the needle valve??


Also why did it got all the way to 8.0??

Also how accurate at the pH test liquids? I calibrated my probe before using it but what the probe says vs the test liquids is off. Probe reads 7.6 while test liquids show about 7.2.

 

[Fishyfanatic]

Yes, control it with the needle valve.

 

[JRagg]

I had this problem and killed fish by doing it incorrectly.

1) Close the needle valve all the way
2) Slowly open the regulator a little at a time until you get up to about 10-20 psi on the second gauge. Sometimes the gauge needle will stick a little bit, this can be fixed by tapping the gauge glass lightly with your fingernail.
3) Once you have a consistent pressure (not changed over 5-10 minutes) slowly start to open the needle valve to achieve the desired bubble count.

What you don't want to do is control it solely with the regulator. This is a sure fire way to have it not work properly. At least you've got a pH controller to keep your pH from going too low. Good luck and feel free to ask as many questions as you need in order to get this right.

 

[dapellegrini]

^^ Yep. You need to control both levels independently. The important thing is that you have enough pressure behind your needle valve to keep it from trickling to a stop. This should not effect your bubble count as you should be fine tuning that with the needle valve.

With the SMS122, it will be much more accurate than your test kits. Do you have any reason to believe that they pH meter was not calibrated correctly or that the tip was allowed to dry out? I use Omega calibration solutions for 7.0 (on the front) and 4.0 (on the back) and all is well. When I first got mine I just calibrated the 7.0 with the little sack that came with it and that seemed to work fine. If you have anymore of your calibration liquid, you could try using that in your pH test kit to see if there is a dependency. That is really the only way you will figure that one out, though I would trust the meter before the cheap test kit...

8 BPS is quite high. I have mine set to 3-4.

 

[rkilling1]

What JRagg said.

I just wanted to add: make sure you check for leaks on the whole setup.

 

[Atl300zx]

Lets hope all my fish are alive when I get home from work. only 50 more minutes.

I dont wanna lose my Angel, Balas, or Silver dollars.....one of my silver dollars is over 5 years old. he is an OG


Update: Just got home, i only lost a Black Molly. This fish has been having seizures for months so no huge loss.

Also my heater seems to be crapping out on me. the tank was 81.6 degrees when i came home, i turned the knob all the way down on the heater and it still didnt click off. Perhaps the thermostat portion of it is broken. i unplugged it for now.

About the pH meter. I am pretty sure the probe was dry when i took it out of the package. it has a protective cover on it, but it definately didnt look moist or wet. What can i do to make sure it is good? i dont have the 7.0 pH solution anymore.

 

[dapellegrini]

The probe comes with a special cap on it. Once you have removed the cap and rinsed off the crystals you do not want to let it dry out (or so I read). I would order a 475ml bottle of 4 and 7 reference solutions. Here is where I got mine:

http://www.omega.com/pptst/PHA4_7_10.html

You really need to calibrate the thing correctly. If it is still acting up after that, it may be defective (though I am sure it happens, I have never heard of one being bad out of the box)...

 

[Mr.pH]

The only way to be sure your pH electrode works OK is to use two calibration solutions. Not calibrated pH meter can b more dangerous than no pH measurements at all.

Also how accurate at the pH test liquids? I calibrated my probe before using it but what the probe says vs the test liquids is off. Probe reads 7.6 while test liquids show about 7.2.

I am not sure I follow you. Can you describe what you did in details? Calibration should be described in your pH meter manual, in case it is not you may try to follow this http://www.ph-meter.info/pH-electrode-calibration procedure.

 

[Atl300zx]

More details in this thread