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how to stop pH swings?


s3xtcy

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hey everyone, this is also posted in the DIY section but thought I might get answers faster in here :)

Ive added co2 to my tank (via DIY) and its working great, however overnight the pH went from 7.0 to about 6.2, which is the 2nd lowest on my chart, this afternoon when i checked it its up to about 7.4, bit too much of a pH swing for the fish to be happy with?

Should it calm down by itself or is there something I can do to stop it fluctuating so much?

ive read that if i stop the co2 overnight it can fluctuate just as much?

thanks for the help :)

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thanks, i was just going to open the lid slightly so the co2 goes into the air rather than into the tank, but i dont want pH swings, even if it is safe :) sooo.. ill just leave it running, cross my fingers, and do a pH test in the morning :)

With your co2 from a bottle, what is the advantage of turning it off at night? do you get pH swings? im wanting to go to a sodastream setup soon with a regulator and solenoid so it can be with the lights :)

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I found that 1 tsp yeast (as you wrote in your other thread) was too much..

The many yeast cells consumes the sugar very fast causing lots of co2 and a rapid drop in pH..

If you use less yeast (perhaps 1/2 or 1/4 tsp) then the yeast will still comsume all the sugar but over a longer time and your pH spike will be smaller.

So that's how it works, you just have to experiment a bit to what size bottle and what amounts works best for your tank size/situation.

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As a part time brewer in a previous life I can explain. Yeast multiplies in the presence of air, so a small amount of yeast will become a lot of yeast until you seal the bottle and exclude the air. When sealed from air it ferments the sugar and produces equal volumes of CO2 and ethanol. The sugar you use is a complex sugar so the yeast has to split it to simple sugars before fermenting it so that will slow the reaction slightly I guess. Brewers often use invert sugar which is simple sugars and ferments quicker. You can also feed the reaction by adding food for the yeast (yeast nutrient) that you can buy from a brewers supply shop. A small amount of marmite is the cheapest. Wine yeasts are stronger than beer yeasts and will ferment more sugar for longer. The yeast will ferment until it runs out of sugar or is inhibited by the amount of ethanol present. Make wine and waste not assuming you are old enough.

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haha thanks, yes im 21 however im much more of a beer man :) however I was under the impression it took alot longer to brew beer and wines than the runtime of my fishtank co2? haha thanks :) ph is still down thismorning (bottom of my chart) so maybe it will stay lower rather than higher? am i correct in saying shells raise the pH slowly and naturally? thanks :)

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Well what I do with my DIY C02 setup is unscrew the cap on the top of the bottle after I turn the lights off at night on the tank. Cutting the C02 really does help keep the PH in my tank stable. I have run tests to confirm this...

My understanding for this is, the plants do not use the C02 in the tank at night, therefore, the C02 left behind takes its time to disapate from the tank water. (I'm going to leave KH out of this to keep things simple)

For example, my PH at the end of my light cycle is 6.2, in the morning before the lights come on it sits at around 6.4. I tested the tank over the course of a week and readings averaged out around the same, and never a variance of more than .1

My tank is 300L and is heavery planted, so this will have an impact on the outcome of my results. However, I'm pretty happy with DIY at the moment.

Cheers,

F

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thanks everyone, my apologies for not understanding this sooner!

I have done a pH test thismorning with it very low (6.0 on my chart - as low as it will go (yellow)) and another thisafternoon with the exact same results, i have some crushed shells somewhere (maybe in my other tank) that I will grab and put in here, this tank is a 305litre, lightly planted :P with a pretty average stocking level, i think i will leave the co2 on 24hrs for the next week or so and see how things go, and if im still not happy with the swings then ill shut it off at night and see what happens, everyone agree this is a good idea?

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Dude if your pH is so low that your test kit is maxing out and you have to start adding coral to get the pH up again you are putting too much CO2 in there in the first place!

Make a new batch. This time with 1/2 tsp yeast. Don't add coral. Problem solved.

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thanks everyone, my apologies for not understanding this sooner!

I have done a pH test thismorning with it very low (6.0 on my chart - as low as it will go (yellow)) and another thisafternoon with the exact same results, i have some crushed shells somewhere (maybe in my other tank) that I will grab and put in here, this tank is a 305litre, lightly planted :P with a pretty average stocking level, i think i will leave the co2 on 24hrs for the next week or so and see how things go, and if im still not happy with the swings then ill shut it off at night and see what happens, everyone agree this is a good idea?

Your PH will be at it's lowest point in the morning if you are leaving your C02 on over night and whist the lights are off. If you think your PH is "too low" I would recommend disconnecting your C02 when you turn your lights off at night. Do a test the next morning, your C02 should be a little higher.

I would not recommend adding shells to your tank if you are running DIY C02 before trying everything else!

You should also measure your tap water to see what PH it's coming out of the tap at. You will need to stand the water for at least 12hrs before testing.

Do you have a KH test kit?

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