s3xtcy Posted March 28, 2011 Report Share Posted March 28, 2011 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 Quote Link to comment Share on other sites More sharing options...
Joshlikesfish Posted March 28, 2011 Report Share Posted March 28, 2011 Not good for the fish. One of the other members will explain it better but you need to increase your kh. That can be done using crushed shell from your lps/lfs Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 28, 2011 Report Share Posted March 28, 2011 That range is no problem with CO2 being added. My tank could vary more than that at times. Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted March 28, 2011 Report Share Posted March 28, 2011 Get a broad range tester that will give you a better indication as far as what's going on with the pH. That range is quite normal and nothing to be worried about. Quote Link to comment Share on other sites More sharing options...
Joshlikesfish Posted March 28, 2011 Report Share Posted March 28, 2011 I always pH changing from 6.2 to 7.4 over a short period of time was bad? I've heard of many people have troubles because of it Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 28, 2011 Report Share Posted March 28, 2011 When you inject CO2 it forms carbonic acid and lowers the pH. That lowering of the pH is used as a way of measuring how much CO2 is getting added and those figures are pretty normal. Quote Link to comment Share on other sites More sharing options...
s3xtcy Posted March 28, 2011 Author Report Share Posted March 28, 2011 oh thats good news then so leave it running overnight? the plants were pretty much dead, and today they appear much greener (on the parts that arnt brown haha) maybe im just seeing things though Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 28, 2011 Report Share Posted March 28, 2011 I use CO2 from a cylinder and it turns off when the lights go off. Diy cannot be turned off at night or it will blow the bottle up (unless you run it to waste). If you run it continuously you will not get so much variation in pH. Quote Link to comment Share on other sites More sharing options...
s3xtcy Posted March 28, 2011 Author Report Share Posted March 28, 2011 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 Quote Link to comment Share on other sites More sharing options...
GZ_Loach Posted March 28, 2011 Report Share Posted March 28, 2011 Plants use co2 during the day (lights on) and expell oxygen, at night (when lights go off) they absorb oxygen and expell co2 Quote Link to comment Share on other sites More sharing options...
s3xtcy Posted March 28, 2011 Author Report Share Posted March 28, 2011 ok. so why should I have less pH swings if I leave it on overnight? Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted March 28, 2011 Report Share Posted March 28, 2011 Because it will be in equilibrium with your KH. Adding more CO2 within reason won't lower the pH but talking it away will make the pH bounce back to normal levels over time. Quote Link to comment Share on other sites More sharing options...
s3xtcy Posted March 28, 2011 Author Report Share Posted March 28, 2011 ok, so the pH should settle down over a few days, take a reading and adjust with shells or something else if needed to keep a constant pH? Thanks for the help everyone, i feel a bit dumb on this :facepalm: Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted March 28, 2011 Report Share Posted March 28, 2011 I personally would just ignore it. I do on my tanks. Quote Link to comment Share on other sites More sharing options...
s3xtcy Posted March 28, 2011 Author Report Share Posted March 28, 2011 haha that sounds easy thanks Phoenix, your a wealth of information Quote Link to comment Share on other sites More sharing options...
hovmoller Posted March 28, 2011 Report Share Posted March 28, 2011 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. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 28, 2011 Report Share Posted March 28, 2011 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. Quote Link to comment Share on other sites More sharing options...
s3xtcy Posted March 28, 2011 Author Report Share Posted March 28, 2011 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 Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 28, 2011 Report Share Posted March 28, 2011 The shells will react with the carbonic acid from the CO2 and make the water harder. Quote Link to comment Share on other sites More sharing options...
FraserNZ Posted March 28, 2011 Report Share Posted March 28, 2011 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 Quote Link to comment Share on other sites More sharing options...
s3xtcy Posted March 29, 2011 Author Report Share Posted March 29, 2011 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 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? Quote Link to comment Share on other sites More sharing options...
GZ_Loach Posted March 29, 2011 Report Share Posted March 29, 2011 Do u have good lighting and ferts? co2 won't get used if the plants don't have enough light/ferts Quote Link to comment Share on other sites More sharing options...
hovmoller Posted March 29, 2011 Report Share Posted March 29, 2011 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. Quote Link to comment Share on other sites More sharing options...
FraserNZ Posted March 29, 2011 Report Share Posted March 29, 2011 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 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? Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 29, 2011 Report Share Posted March 29, 2011 As stated above, CO2 without good lights and ferts is realy a waste of time. I would suggest you get the whole three right and not worry about the pH or get rid of the CO2 and lose the fluctuations problem. Quote Link to comment Share on other sites More sharing options...
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