Is my injection rate too high?

[Tally]

Hi all,
Over the last few days I have started adding CO2 into an existing planted tank which has fish and rsc.
I have just read in another post that a ph test should be done on tank water that has stood for 12 to 24 hours, this I did not do.
Does this profile appear to be safe for the livestock?
14:00 ph7.9
15:00 ph7.9 CO2 on
16:00 ph7.2
17:00 ph7.0 lights on
18:00 ph6.9
19:00 to 22:00 ph6.85
23:00 ph6.85 CO2 off
24:00 ph7.1 lights off
01:00 ph 7.4
I am using a Semlos ph meter which is a rather inexpensive brand. Just before lights off, the drop checker is still a lime green. The fish seem to be doing fine although after lights off I can't really observe their behaviour.
I have only been injecting at this rate for the last two days.
Any advice much appreciated.

Thanks,Paul

 

[Jayefc1]

Sounds ok to me no gasping fish ph drop of 1 = 30 ppm and that is what your looking for drop checker lime green now just watch and see what is happening in the tank don't get to stuck up on everything else what ferts are you using

 

[oscarlloydjohn]

Looks good to me, a 1.0 pH drop is ideal.

 

[AverageWhiteBloke]

Both methods of co2 checks at our disposal come with caveats so some discretion needs applied mainly are fish gasping and are the plants showing any signs that co2 isn't right like holes in leaves etc.

The drop checker is probably the best way I would say but you have to bare in mind it is only telling you what the co2 levels were in position the drop checker is some time ago allowing for how you personally perceived the colour. Definitely a margin for error. Best place to put it is where you suspect your co2 or flow would be at its worst or maybe move it around the tank a bit now and again. Tanks are dynamic so you could be getting good co2 in an area then not so as plants fill in and block the water routes.

PH profiling is more a real time check than the DC method but also heavily dependant on some other factors for its accuracy. Is the PH pen of a good quality, has it just been calibrated using different ph solutions, some people will take a sample in the tank at the top where co2 is at its highest levels as it escapes into the atmosphere but tells you nothing about lower down in the tank, a sample taken from the tank into a separate container is already losing co2 as you're waiting for the ph pen to stabilise and give you a reading. Again, a lot of margin for error so no real point in worrying about decimal points of PH with these margins.

The two methods can be combined to give us some ball park figures but its a rather large ball park and the plants will have the last say. Just use them as a rough direction to be heading in.

 

[Tally]

Sounds ok to me no gasping fish ph drop of 1 = 30 ppm and that is what your looking for drop checker lime green now just watch and see what is happening in the tank don't get to stuck up on everything else what ferts are you using

The tank is an EA600, so approx 100 litres. I'm using 10ml of the aquascaper complete liquid plant food on a daily basis. I'm also dosing 4ml of TNC carbon to try and combat bba which is one of the reasons I've gone the CO2 route.

Both methods of co2 checks at our disposal come with caveats so some discretion needs applied mainly are fish gasping and are the plants showing any signs that co2 isn't right like holes in leaves etc.

The drop checker is probably the best way I would say but you have to bare in mind it is only telling you what the co2 levels were in position the drop checker is some time ago allowing for how you personally perceived the colour. Definitely a margin for error. Best place to put it is where you suspect your co2 or flow would be at its worst or maybe move it around the tank a bit now and again. Tanks are dynamic so you could be getting good co2 in an area then not so as plants fill in and block the water routes.

PH profiling is more a real time check than the DC method but also heavily dependant on some other factors for its accuracy. Is the PH pen of a good quality, has it just been calibrated using different ph solutions, some people will take a sample in the tank at the top where co2 is at its highest levels as it escapes into the atmosphere but tells you nothing about lower down in the tank, a sample taken from the tank into a separate container is already losing co2 as you're waiting for the ph pen to stabilise and give you a reading. Again, a lot of margin for error so no real point in worrying about decimal points of PH with these margins.

The two methods can be combined to give us some ball park figures but its a rather large ball park and the plants will have the last say. Just use them as a rough direction to be heading in.

Being the first time that I have used CO2, my concern was with the health of the livestock. I'm confident that the drop checker has not strayed into the yellow and I will follow your suggestion of siting it in different areas of the tank.
The meter I used was a Semlos ph pen (£12.99 on Amazon). I did calibrate using the supplied powders but have no way of knowing it's accuracy.
Should de-ionised water have a reading of ph7?
As you have pointed out I took samples from the top because I was getting unstable readings when placing the pen in the tank.

Thanks for the replies

 

[ian_m]

As you have pointed out I took samples from the top because I was getting unstable readings when placing the pen in the tank.

Take some tank water out, in a cup, and measure its pH. Your pH pen may be being affected by electrical interference in the tank. (or unplug everything from the mains and read pH again).

 

[AverageWhiteBloke]

No mate deionised water technically doesn't have a PH, in fact, reliable ph readings are difficult to obtain in very soft water at the best of times. Like I said though do your tests and use the DC but don't get too bogged down in it, it's just not that accurate. Plant health is a better indicator.

Sent from my STH100-2 using Tapatalk

 

[Tally]

Take some tank water out, in a cup, and measure its pH. Your pH pen may be being affected by electrical interference in the tank. (or unplug everything from the mains and read pH again).

I've just ordered another CO2 kit for the EA900. I'll take water samples for the ph testing when I set this one up

AWB.
I will continue to monitor the plants,fish and DC in the 600 then do another profile in a couple of weeks.

Thanks for the help