IE 50% Water change - PH swing

flexbs

flexbs

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Sep 22, 2009
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I have a 65 gallon planted doing really well. My only concern is my water change. I have a 50 gallon drum that I prepare every Friday to have the right temp for Sunday's water change. When I start the water change my PH is between 6.5 and 6.6. After the water change it jumps to 7.9. (I know the swing is because my tap water has a high PH.) It then takes a while for the CO2 to drop the PH. Is this ok? Is there a way to drop the PH in the 50 gallon drum to match my tank?

Thank you
Flex
 
i do the same thing with w/c and im on the ei method aswell
i just chage out 30 % instead of the 50% to avoid the huge ph swing.
 
You shouldn't have to worry about the difference induced by CO2. If you are worried, turn off the CO2 to your tank a couple hours before the water change. Check your pH though 'cuz if the pH is still low after the CO2 has off-gassed, then you have some other reactions going on in the tank, possibly too much organics, that are keeping the pH down so you might want to consider more frequent water changes with a lower % change or change whatever it is causing the low pH (high bioload/overfeeding?). btw, you could inject CO2 into the holding tank but that's really not necessary,
 
Don't take into account the tank waters pH due to its co2 concentration when comparing your tank water to your drum water. Measure your pH before your co2 comes on for the day in your tank, then compare that to the ph of your drum water...that is the total pH swing that you want to monitor. IMHO, 6.5 to 7.9 is not that big of a swing.
 
beviking said:
You shouldn't have to worry about the difference induced by CO2. If you are worried, turn off the CO2 to your tank a couple hours before the water change. Check your pH though 'cuz if the pH is still low after the CO2 has off-gassed, then you have some other reactions going on in the tank, possibly too much organics, that are keeping the pH down so you might want to consider more frequent water changes with a lower % change or change whatever it is causing the low pH (high bioload/overfeeding?). btw, you could inject CO2 into the holding tank but that's really not necessary,
Click to expand...
great to see you here beviking.... and he is 100% correct.
 
Measure KH, not pH.

I do 50-80 % water changes and I have high grade CRS's, rare plecos, and I breed these fish. Got fry to prove it.

Anyway, fish have to balance their salt content internal/external, TDS would also work to some extent in place of KH.

CO2 is not and never has been a salt.
It can affect pH, but only in the context of us adding it beyond the normal levels via enrichment.

We add CO2 for plants, not to control pH.
I've been doing massive water changes and have pH changes of 1 full degree every day in less than 1 hour.

Fish breed and have lived a very long time and are very healthy in all my tanks, after doing this, as well as thousands of other folks.........not one has had an issue related to this supposed myth about pH change in 15+ years.

Regards,
Tom Barr
 
Thank you all for the replies.

Tom, you are right with your comment (thousands of others do the same with no issue). I just wanted to make sure. I've been doing EI since January but recently I had a fish die the next day after a water change. I guess that is just the nature of things. All my parameters are excellent so I guess I wanted to blame something. I will check my KH just in case.

FYI- I learned all about EI from BarrReport :)

Thanks again
FLEX
 
Water changes can do other things, for example, adding improper dechlorinator/amount etc. Seachem and Amquel are the two most used brands, never an issue.

If you do large weekly water changes..........then the tap and the tank water should be very close. Sometimes they change things at the WTP, but it's typically when they blend or mix and try to keep the alkalinity stable.
Still, most tap water supplies tend to be rather stable, easy for the operators to run the various processes if they do this.

You might also read the "myths and misconceptions about EI" as well.
Things I've never said...that some folks have been telling others for a long time now:wall:

Regards,
Tom Barr
 
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