New to CO2 injection: A few questions

[Ormarr]

I recently installed my first pressurized CO2 setup this afternoon (completed with Milwaukee SMS122 PH meter).
I am still confused as to how I would determine how much CO2 is being disolved into my tank.

If my PH is 7.2 at the moment, with KH of 3 degrees, this would be roughly 5.6 ppm of disolved CO2. 
What would be the best way for me to increase the CO2 disolved to about 20ppm or so?
If it helps any, I have about 2 bubbles per second being added to the tank.

Thanks!

[jetstream]

What kind of hardware or means you are using to dissolve the CO2 now? And how big is your tank? 

[Ormarr]

It is being fed into the intake tube of my Eheim Classic canister filter (hence being dispersed via the spray bar) and it's in a 75g tank.

[BigDaddy]

I would say something is outgassing your CO2.  With 2 bubbles per second, you should be measuring more CO2 than that.

Do you have any airstones or significant turbulence at the water's surface?

[Aquaviewer]

I'm not familiar with the Milwaukee 122 controller, but if it is like my Pinpoint you need to set the range (an upper and lower limit).  If your KH is 3 and you want to get your CO2 up 30 ppm then you want to target your pH to 6.5.  This is done by setting a range on the controller to govern when the CO2 comes on. 

For example if you want you pH to be 6.5, you would set the range to be 6.4 and 6.6.  When the pH goes above 6.6, your CO2 will come on and keeps injecting until the pH gets down to 6.4 when it would shut off.  This would keep you levels in the range you want.

If you have set these ranges and the CO2 is on and not driving the pH down to meet your targets you may also want to revisit the design of your diffuser as you are likely getting too much off gassing and not much mixing in the water.

[Ormarr]

I see now.  So, if I keep injecting CO2 until the PH drops to 6.6, I should have roughly 23ppm of CO2 dissolved in the water (since my KH is 3)?

[Aquaviewer]

I see now.  So, if I keep injecting CO2 until the PH drops to 6.6, I should have roughly 23ppm of CO2 dissolved in the water (since my KH is 3)?

Yes.  You should notice the shift occurring.  It shouldn't take days, more like hours.

[dan2x38]

Like BigDaddy said are you using any airstones, bubble wands, or any other water turbulence? Where is your spraybar positioned?

[Ormarr]

No airstones, I took them out when I added the pressurized CO2.  The spray bar is turned slightly downwards at the moment.  Which way should I aim it? I do have an AC110 on at the moment, but I make sure the water level is high to minimize CO2 loss.  I am going to get another canister as soon as the holidays are over.  I supposed I should have mentioned the setup was only running for about 3-4 hours (yesterday was the first day).  I didn't quite get what the chart meant, but it is much clearer now.

I usually read that people turn off the solenoid at night (when the lights go off).  If I have a PH controller, do I still need to do this or do I just let the solenoid turn tje CO2 on and off based on what the PH is at?

[Aquaviewer]

If I have a PH controller, do I just let the solenoid turn tje CO2 on and off based on what the PH is at?

Yes

[BigDaddy]

Depends on if you want your pH at a steady level or if you want to conserve CO2.

There is no point in injecting CO2 into the tank when the lights are off.  If you want to save CO2, have your system on a timer where the controller turns on a couple of hours before lights on (to start bringing CO2 levels up to optimal for lights on) and turns off a couple of hours before the lights go off (again to save CO2).

A bit more work, but you are likely going to save a lot of CO2 in the long run.

[Aquaviewer]

Depends on if you want your pH at a steady level or if you want to conserve CO2.

There is no point in injecting CO2 into the tank when the lights are off.  If you want to save CO2, have your system on a timer where the controller turns on a couple of hours before lights on (to start bringing CO2 levels up to optimal for lights on) and turns off a couple of hours before the lights go off (again to save CO2).

A bit more work, but you are likely going to save a lot of CO2 in the long run.

This is not necessarily true.  The point of the controller is to only inject CO2 as required to maintin your pH.  While yes, it will come on at night to do so, it is also only comming on as required during the day to maintain pH levels as opposed to running all day at a set bubble rate.  Therefore, CO2 consumption is likely equivalent to running on a timed system when you consider total time on.

There are advantages and disadvantages to both systems.  Pick whichever one fits your routine.

[Ormarr]

How long should it take for the PH to reach the set point?  I've had the CO2 on all day and it hasn't moved from 7.1  Either I'm doing something wrong or the CO2 is not getting dissolved into the water.  The broken down bubbles seem to float back to the surface and stay there.  Am I being impatient or am I missing something?   

[fischkopp]

You may want to check your pH probe. Redo the calibration. Sometimes a probe becomes dry, soaking it overnight in pH4 solution will help to reactivate it in this case.

You may also increase the buble rate a bit and see if it helps.

[Ormarr]

I didn't get a PH 4 solution, only PH 7.  The probe was dry (since it was brand new, I put it in yesterday).  I did the calibration, rinsed the probe and then put it in the tank.

[charlie]

I didn't get a PH 4 solution, only PH 7.  The probe was dry (since it was brand new, I put it in yesterday).  I did the calibration, rinsed the probe and then put it in the tank.

Re calibrate the probe again, a dry probe should be soaked for a while then calibrated, i have a fairly accurate portable PH pen , i can cross reference your controller if you like.LMK
Regards

[Ormarr]

I re-calibrated the probe and it dropped from 7.1 to 6.8.  Will see what happens overnight and tomorrow.

Thanks for info. everybody 

[Ormarr]

The CO2 was on all night and the controller never moved from 6.8.  Perhaps I didn't leave the probe in the PH 7 solution long enough?  How long should I leave it in there for calibration?  Also, where could I get PH 4 solution to help with the calibration?

Thanks.

[fischkopp]

I got some PH4 in a hydrophonic gardening store, BriteLight on Merivale.

But that your pH doesnt change after 24h+ operation is indeed strange ... you can try to test the probe in other tanks/tap water to see if its a probe problem (it should give you a different pH) or maybe something else on the adjusting/setup side. Check you CO2 connections again and make sure you have no leak anywhere.

[Ormarr]

The probe does change when I place it into PH7 solution.  I'm fairly certain the CO2 is making it to the tank as I can see the bubbles being sucked up the canister filter intake.  How crucial is it to set the slope reading (because I didn't, since I had no PH4 solution).  Maybe I'll get some PH4 solution after work and try again.

[Toss]

Try to turn off AC110 for a day and see if that improve the CO2 concentration in the tank.

[Ormarr]

Would having filter floss in my AC500 or Canister filter somehow impede the flow of CO2 bubbles?  I removed the floss I had in my Eheim but still have some in my AC500.

[jetstream]

Since you are using a ph controller, you can check the controller to see it's on all the time or it's on an off intermittent. At least you get rid of one of the possible causes! If it's on all the time, you know right the way, you need to increase the Co2 more and see.

[Ormarr]

Well, it turns out my AC110 was out-gassing more than I thought it would.  I turned it off during the day and the PH dropped to 6.5 without a hitch.  Is it a good idea to turn the AC110 on again when the lights go out to out-gas some of the CO2 at night?  I will eventually get another canister (probably after the holidays).

Thanks for the help/info. everyone!

[babblefish1960]

Yes you could put the ac110 on a timer to match the lights going out and coming on again, you could also put that canister under the tree and label it "for the fish from Santa", no one ever questions gifts from the big guy!

[Ormarr]

Problem is, the big guy has been buying a whole lot of fish related products throughout the year.  Mrs. Clause is starting to catch on. 

[dan2x38]

Yeah I wore out that Santa fish scenario cover story awhile ago now...

Sometimes it is hard to get the ACs going without priming. Make sure you are around the first couple times. I had a power outage waitied around but then had to go out for an appointment. When I got back 2 hours later one of my ACs was running dry the powered come on... Yikes... it was OK in the end though, gladly...

[Toss]

I would recommend not putting a filter (any kind) on a timer. Filter is meant to be on 24/7 with exception of cleaning time. It is not good for the bacteria live in the media, especially hang on back (HOB) type since some water drain back to the tank as soon as you turn it off. Also there is a chance that the impeller might not restart again (like Dan said) due to some debris settled inside the impeller housing. If you have some MTS (snail) and your aquaclear is off, there is a big chance that one of them will sneak into the impeller housing and jam it. When the impeller is jammed for a long period of time, the housing will get really hot and bad things usually happen after that.

[Ormarr]

One last question...(for now  )

Say the PH drops to 6.6 (desired target, about 25ppm of CO2).  If I wake up the next morning and the PH is 6.7 (20ppm or so), is this a good thing or is it best to release some of the CO2 at night and start again from 7.2 (where it usually goes back to with the HOB on at night)?

[Glouglou]

Sorry to rain on the conversation, but what is the purpose of a complicated an expansive PH controller when you can acheive the same with bubble count, solenoid and a simple Drop Checker?

[dan2x38]

One last question...(for now  )

Say the PH drops to 6.6 (desired target, about 25ppm of CO2).  If I wake up the next morning and the PH is 6.7 (20ppm or so), is this a good thing or is it best to release some of the CO2 at night and start again from 7.2 (where it usually goes back to with the HOB on at night)?

If your worried about O2 levels put an airstone or bubble wand on a timer to start after lights out. Alot easier than an AC.

[BigDaddy]

One last question...(for now  )

Say the PH drops to 6.6 (desired target, about 25ppm of CO2).  If I wake up the next morning and the PH is 6.7 (20ppm or so), is this a good thing or is it best to release some of the CO2 at night and start again from 7.2 (where it usually goes back to with the HOB on at night)?

As long as you stay above 15ppm, you are fine

[Glouglou]

I LIKE MY LIFE COMPLICATED!