# CO2 and ph fluctuations when changing water



## Oniard (Jan 23, 2021)

Hey,

I'm currently planning a discus tank for display. The tap water where I live has a slightly high ph of 7.8. To combat it I'm planning to use CO2 injection as that would also help the plants grow. If I reach 30ppm CO2 that should theoretically reduce ph .8 to 7.0. I'm however unsure of how the fish will react when I'm going to change the water because I would imagine that it would take some time for the tap water to get gassed with CO2 and drop in ph.

Lets say i change 50 percent of the water each time, that would result in a change of .4 in ph. Some places they say that a change above .3 can be deadly and other places they say that its only the kh change that is dangerous and not to worry about the ph because CO2 doesnt impact kh. 

Any help will be appreciated.


----------



## 20yearfishexpert (Jan 21, 2021)

Try adding a little bit of beneficial bacteria as a booster and make sure the tap water is de-chlorinated.


----------



## Oniard (Jan 23, 2021)

Some good bacteria would definently be good and im fortunate enough that i live in Denmark where all water is chlorine free so de chlorinator isnt neccesary. Do you know if the PH swing will be dangerous?


----------



## 20yearfishexpert (Jan 21, 2021)

Yes, I would attempt to make the swing as gradual as possible by only doing a little bit of a water change/ bacteria add in at a time. You can buy bacteria online or at a local pet store. I only use store-bought bacteria as a booster when cycling a fish tank but it works perfectly in your case as well.


----------



## Rayrodrich (Jul 27, 2021)

I have similar high alkaline ph tap water where I live in Florida and currently maintain a 75 gallon tank with six jumbo wild caught discus at 6.8 with Seachem Discus buffer. Two 35% water changes a week with four teaspoonfulls of buffer each time. They are happy campers. It is stable at 6.8 every day.

Sent from my LG-H932 using Tapatalk


----------



## Mark Nicholls (12 mo ago)

Changing water will NOT affect bacteria levels


----------



## chauceringram (11 mo ago)

Great info guys and a pleasure to read.


----------



## ydesun (6 mo ago)

While utilizing a Python to do water changes is PH something to truly stress over. I realize PH is significant and huge PH swings are not great for fish, and so on.. The explanation im asking is b/c I understand alot of individuals utilize a Python and I cannot see their tap PH being equivalent to their tank PH. My tap PH is in the upper 8's and my tank is in the lower 6's (with CO2 during the day). I realize that PH swings brought about by CO2 don't impact fish. At this moment I have another tank that I keep the water in for seven days so the PH will kill/lower. IMO I would figure there would be a PH crash during the 24-48 hours after the WC. Any considerations would be greatly valued. Much obliged 


Tutuapp 9Apps Showbox


----------

