pH drop via CO2 speed? - The Planted Tank Forum
 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 06-04-2017, 11:28 AM Thread Starter
Planted Tank Obsessed
 
PTrader: (3/100%)
Join Date: May 2013
Location: Western PA
Posts: 478
pH drop via CO2 speed?

How fast can I drop my pH via CO2 injection before it is too dangerous for fish? Generally I see people shoot for an hour, is there is a reason for that? is slower safer? Will a sudden drop cause delicate fish stress?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
aja31 is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 06-04-2017, 11:42 AM
Planted Tank Enthusiast
 
dcutl002's Avatar
 
PTrader: (1/100%)
Join Date: Apr 2014
Location: Smithfield, Va.
Posts: 687
I would say an hour, maybe two. I try not to change parameters too fast so the fish have time to adjust: I tend to think changes that are too fast may give the fish some stress. I use a drop checker which takes a couple of hours to change color anyway. Alas, my drop checker is usually blue when the lights come on at 6:00 AM and is green somewhere around 10:00 AM.
dcutl002 is offline  
post #3 of 9 (permalink) Old 06-04-2017, 11:44 AM
nel
Planted Tank Enthusiast
 
nel's Avatar
 
PTrader: (0/0%)
Join Date: Jan 2016
Location: Poland
Posts: 745
It's not the pH drop, CO2 pH drop is harmless, what is dangerous is sudden lack of oxygen and high CO2 content.

But real reason is you would have to change the bps to achieve fast saturation and then keep it and not overdo it. So you would have to turn the valve on (that can be automatic) let it go for short time on high bps and then adjust bps by hand to make it stable every single day. Doesn't sound like fun, right? ;-) With stable bps you have to start 1-2 hours before lights turn on.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 120x48x60 cm

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 30x30x30 cm + 30x30x20 cm,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 33x21x22 cm
nel is offline  
 
post #4 of 9 (permalink) Old 06-04-2017, 01:57 PM
Algae Grower
 
osmosis's Avatar
 
PTrader: (0/0%)
Join Date: Apr 2017
Location: Clovis, CA
Posts: 117
aja,

I am using an APEX controller just like you so I was looking to set my bps to get the pH down over the course of 60-90 minutes before the light came on. That meant a duty cycle of about 30% on time once i got down to 6.2. It would have gone lower without the controller. Then I had my ich problem. With the temp up from 78 to 87 deg, my pH now drops in about 30 minutes even after slowing down the bps. How fast it drops also appears to be affected by surface agitation etc. Even with the fast drop, I have seen no indication that it bothers the fish in any way. As Nel said, I think they would be more sensitive to rapid changes in CO2.

When my temp comes back down I think I will set my bps so that it wont overshoot too much if the pH probe fails (calibration shifts the wrong way).


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
osmosis is offline  
post #5 of 9 (permalink) Old 06-04-2017, 02:07 PM
Planted Tank Guru
 
PlantedRich's Avatar
 
PTrader: (2/100%)
Join Date: Jul 2010
Location: United States
Posts: 12,183
I feel we often overwork our brains on questions of this sort. I do go with a slower bubble count and let the controller watch it for me. But then I don't really feel any need to work things so hard that the plants have an immediate supply of a high level of CO2 at first light. Growing things is a practice in patience. If my plants do not grow to the max for 30-40minutes each day, do I want to sweat over such a small thing at the expense of living a couple years less?
I've learned to set back and watch thing grow and that allows me to relax and enjoy the trip more. If I'm constantly pressing for the max, I stand a much better chance of overshooting and killing the whole thing!
PlantedRich is online now  
post #6 of 9 (permalink) Old 06-04-2017, 04:21 PM Thread Starter
Planted Tank Obsessed
 
PTrader: (3/100%)
Join Date: May 2013
Location: Western PA
Posts: 478
So the problem i'm having is that my pH is bottoming out before I get it to the level I want. I needed to up the bps to get it to drop far enough, but that puts the initial drop at ~45 minutes. If its slow enough that it takes 2 hours I can only get it down to 7.6 instead of the 7.2 I want. That was the main reasoning behind my question. Since it is controlled by the pH meter I can crank it up and then just have a low duty cycle to keep it there throughout the day, but I wasn't sure if the fast drop in the morning would be bad for the fish. I have good surface agitation (ripples) and my sump is a torrent of bubbles (Durso standpipe) so I suspect I have plenty of oxygen in the water... wish there was an easy way to measure that.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
aja31 is offline  
post #7 of 9 (permalink) Old 06-04-2017, 04:37 PM
nel
Planted Tank Enthusiast
 
nel's Avatar
 
PTrader: (0/0%)
Join Date: Jan 2016
Location: Poland
Posts: 745
If you have pH meter then don't bother with turning CO2 off for the night. Mine is set to pH 6,30-6,45 when the lights are on and 6,45-6,60 when they're off. This way there's no swing and I don't have to wait for the CO2 to get to the right levels.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 120x48x60 cm

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 30x30x30 cm + 30x30x20 cm,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 33x21x22 cm
nel is offline  
post #8 of 9 (permalink) Old 06-04-2017, 10:29 PM Thread Starter
Planted Tank Obsessed
 
PTrader: (3/100%)
Join Date: May 2013
Location: Western PA
Posts: 478
Followup question... How much fluctuation is acceptable throughout the day with CO2? I have my controller turn off the CO2 at 7.2 and stay off for a minimum of 5 minutes before turning back on if necessary. However when it does turn back on it pumps in CO2 until the pH drops below 7.2 again. However since the pH probe is in the sump by the time it starts to drop there is already more CO2 in the tank so even when it turns off it keeps dropping, down to ~7.08 before finally bottoming out.

Is the only way to limit this to put the probe into the tank itself? I was trying to avoid any wires in the tank, but the pH is not as stable as I was hoping with the probe in the sump.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
aja31 is offline  
post #9 of 9 (permalink) Old 06-04-2017, 10:41 PM
nel
Planted Tank Enthusiast
 
nel's Avatar
 
PTrader: (0/0%)
Join Date: Jan 2016
Location: Poland
Posts: 745
I wouldn't worry about it, I give mine 0,15-0,25 margin (0,15 range with 0,05 hysteresis), just set it so the lowest pH you get doesn't mean killer amount of CO2. When you will have some time to observe your tank carefully try setting pH lower and lower, when you reach the point where fish are starting to act somehow weird (breathing heavily or just moving slowly) - stop there. This is what you DON'T want. So set it even 0,2-0,3 higher and that should be safe. Mine has a sound alarm too, so when it somehow reaches 6,00 (like completely loose valve or something) it will inform well... everybody around.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 120x48x60 cm

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 30x30x30 cm + 30x30x20 cm,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- 33x21x22 cm
nel is offline  
Reply

Tags
None

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome