Turning CO2 off at night. What about Ph changes?

jnms

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I am not too worried about low / high ph - as most fish seem to adapt and cope pretty well.

However there is one thing I don't get with the whole CO2 deal. Turn on the CO2 during the day achieve 30ppm and the Ph will certainly drop. Then turn the CO2 off at night then the Ph will rise again.

Surely the flucuating Ph levels will harm the fish?
 

George Farmer

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The pH swings do not harm the fish at all.

It happens, sometimes to a bigger extreme, in nature.

Because the pH swing is gradual, the fish adapt very well. However, if you suddenly put a fish from pH 6 into pH 8 instantly, then there would likely be issues - but this isn't the case with CO2 injection, of course. The likely pH difference would be around 1 max. i.e. from pH 6.5 > 7.5 over the course of a few hours.
 

jnms

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Ok great, thanks for that.

Currently I am adding DIY CO2 via a yeast-mix. So I don't need to worry that the Ph changes from one day to the next? I even have discus in the tank. Non of the fish seem bothered by the Ph changes - but it has been a cause of concern for me.

Got me thinking about getting pressurized CO2, but then I realised the Ph would change overnight anyway.

So - Ph changes that rise and drop day to day are not a concern (even for Discus?) so long as it is not sudden?
 

Ed Seeley

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pH changes from CO2 don't seem to effect fish at all. It's the TDS and make up of the water that seems to be the key. I have moved fish from water of similar TDS, one with CO2 and one without, with a 5 minute acclimatization, and they have never had a problem. The pH change doesn't even need to be that gradual IME. However do not move fish between radically different compositions of water or you will cause serious problems.
 

jnms

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Thanks Ed, that actually makes a lot of sense. There is so much conflicting information out there in Internet-land, that it is very easy to become paranoid about the whole Ph game.

Good to know it isn't so much of an issue as it is made out to be...

Thanks
 

Ed Seeley

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No worries, glad to help. One thing to bear in mind is that if you can afford to get it then pressurised CO2 is way better for you tank in lots of ways. Stable and high enough CO2 is one of the key factors in vibrant plant growth and reducing algae. Pressurised CO2 allows you pretty much total control of the CO2 levels in your tank, including turning it off overnight (which I personally always want to do and would definitely want on a tank full of discus). Also, if you fit a solenoid, the CO2 will be turned off if there's a power cut and the lights and filters go off, preventing an overdose then.

It's also way more convenient as you're not constantly changing yeast mixes and much easier to control. Once you work out the cost (not even incluidng your own time) of constantly mixing up yeast mixes as well it doesn't come out much more expensive in the long run - it's just much more expensive to set up.
 

George Farmer

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Totally agree with Ed there about pressurised CO2.

It's probably the single biggest step one can make to help achieving success in the planted tank hobby.
 

Dave Spencer

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jnms said:
Thanks Ed, that actually makes a lot of sense. There is so much conflicting information out there in Internet-land, that it is very easy to become paranoid about the whole Ph game.

Good to know it isn't so much of an issue as it is made out to be...

Thanks

Personally, I blame TTF for a lot of paranoia and misinformation. It does still have some good info on there, though.

Dave.
 

GreenNeedle

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Lol. Not TFFs fault. Its because its such a huge forum that there are more 'dark age' followers on there than most although I only battle constantly with one of them ;)

One thing I would say though is that if you have discus then I would say your tank is a little too large to be using DIY anyway!!!

AC
 

jnms

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Thanks again for all the replies.

Pressurised CO2 is on the list for some time after Christmas. :)

It still is a real big thing for me to get my head around the fact that Ph swings aren't harmful. Keeping a constant Ph is one 'fact' that was pumped into me again and again right from the first moment.

The yeast CO2 seems to get right around the tank ok. I use two bottles of yeast, going into the intake of a Interpet PF3, it mashes the bubbles up so small that the float around the entire tank. Once the mix is pumping ok - I get a Ph drop of around 1 degree. Moving from 7.9 down to 6.9 - so the DIY is certainly doing something. Though I appreciate pressurised will be much better...
 

vauxhallmark

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jnms said:
Thanks again for all the replies.

Pressurised CO2 is on the list for some time after Christmas. :)

It still is a real big thing for me to get my head around the fact that Ph swings aren't harmful. Keeping a constant Ph is one 'fact' that was pumped into me again and again right from the first moment.

The yeast CO2 seems to get right around the tank ok. I use two bottles of yeast, going into the intake of a Interpet PF3, it mashes the bubbles up so small that the float around the entire tank. Once the mix is pumping ok - I get a Ph drop of around 1 degree. Moving from 7.9 down to 6.9 - so the DIY is certainly doing something. Though I appreciate pressurised will be much better...

As you say, you can be very successful with yeast-generated CO2 - however, once you see how stable and maintenance-free a decent pressurised system is there's no going back! (although I still use yeast on my dump/holding/growing tank.)

Mark
 

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