how much CO2?

[Soeman]

So I started adding CO2 to my aquarium, and a couple of days later 3 of my cardinals died  The rest of my fishes seem to be okay though.

I've got a 30g tank, and I'm using DIY yeast CO2. I _was_ using a DYI diffuser where a powerhead pushes water down a tube in which the CO2 is injected. 100% of the CO2 gets dissolved, but I have no control over how much CO2 is injected. I've devised another diffuser which will allow me the control I desire (by means of releasing excess pressure), but I'm not sure how much CO2 should be provided. Is there a good method of measuring co2 in your tank, or are there any guidelines of how many BBM should be provided per gallon of tank water?

P.S.: I know there's 'recipes' available for how much sugar/yeast/water to use, though these rarely mention how many gallons of tank water they serve. Also, I want to use multiple yeast factories to maintain a steadier flow - the first and last few days of a yeast generator are far less useful than the middle period. By using multiple generators I can keep them at different stages and constantly have good co2 production.

[charlie]

So I started adding CO2 to my aquarium, and a couple of days later 3 of my cardinals died  The rest of my fishes seem to be okay though.

Hi Soeman, are you assuming the addition of DIY CO2 was responsible for the Cardinals death?
If you are only doing DIY with the recommended mixture of sugar to yeast & 1 bottle as a generator for your 30 Gln . tank, i would highly doubt you are generating that much CO2 to cause that.

I've got a 30g tank, and I'm using DIY yeast CO2. I _was_ using a DYI diffuser where a powerhead pushes water down a tube in which the CO2 is injected. 100% of the CO2 gets dissolved, but I have no control over how much CO2 is injected. I've devised another diffuser which will allow me the control I desire (by means of releasing excess pressure), but I'm not sure how much CO2 should be provided. Is there a good method of measuring co2 in your tank, or are there any guidelines of how many BBM should be provided per gallon of tank water?

(1)In my opinion, i think the powerhead reactor would do just fine for your tank & DIY CO2-BTW what type of lights & how much watts?

(2)You need to have a consistent level of approx 30 PPM of CO2 during your lighting period
They are several methods of measuring CO2, each with it`s own flaw, among which the PH/KH chart is the one i stay away from & suggest starting with 1 PH drop for a good reference line you can tweak it later.Below is a link that gets into the details of why the PH/KH chart is flawed & may i say dated, it also explains the 1 PH point drop
http://theplantedtankfaq.com/CO2_FAQ.html
- check question 16 BTW there is tons of useful info on his site
(3)BBM would vary from tank to tank depending on several factors such as light, plants etc.
(4) You would probably need 2 or 3 -1 litre bottles to supply ample CO2 to that tank , again depending on your lights, inter changing them weekly will help to somewhat maintain a consistent level.( tough task with DIY)
Hope that helps, others might have more to offer.

[Toss]

Another point to add to charlie's answer/suggestion is that your plant doesn't require CO2 at night. So if you are planning to get a few bottles going at the same time to get high CO2 in the water during photo period, you must find a way to stop it when the light is off.
In my opinion I don't think the Co2 kill your cardinal, unless some of your sugar yeast mixture got in the tank, you would notice with cloudy water.

[Soeman]

Hi Soeman, are you assuming the addition of DIY CO2 was responsible for the Cardinals death?

Yes. I'd heard from other sources that it was _impossible_ to overdose CO2 with DIY, and was running 2 2L bottles of CO2. When my fishes started dying, I realized "Duh, of course it's possible to overdose with DIY" - just depends on the total number of liters you have feeding how many gallons. To take an extreme example (which is thoroughly unrealistic), imagine using 30 2L bottles to feed the co2 on a 10g tank... clearly this would be enough to overdose the CO2 if it's all getting diffused. I'm using 2L bottles because that is what is most accessible to me.

My fishes have been doing fine for months now, and I'm starting to add more and more plants (the last one was added about a week ago). Aside from the addition of plants, nothing else has been changed in the past month.

(1)In my opinion, i think the powerhead reactor would do just fine for your tank & DIY CO2-BTW what type of lights & how much watts?

I found the efficiency of the reactor to be superb; my only problem with it is the space it takes up in the tank. As it is I dislike having the heater and filter intake sticking into the tank, I'm going to try going with a system that diffuses the co2 into the water outside the tank and then gets pumped back in, but i'm not sure i'll be ahead with this since it'll mean another intake and output :p

My lighting is 2 24" t12 on a 12h cycles (i realize this is long, but I dont really have algae problems). This gives me 40W of t12, but since my tank is extra tall (24"x12"x24") the watts per gallon calculation should actually be done on 20g and not 30g. I've done extensive research on lighting, calculating the lux from my lighting, and the lux requirements for my surface area, and it works out to a medium range of light intensity. One tube is daylight, the other cool white.

(2)You need to have a consistent level of approx 30 PPM of CO2 during your lighting period
... 1 PH drop for a good reference line
(4) You would probably need 2 or 3 -1 litre bottles to supply ample CO2 to that tank , again depending on your lights, inter changing them weekly will help to somewhat maintain a consistent level.( tough task with DIY)

Hmm... I was running my co2 though the night, and it was in the morning that i noticed the dead fishies; this might have been the main source of my problems 

My initial pH was over 8 (probably around 8.3) and with CO2 it was around 7.5. My only I'd read the site you referenced before, and was familiar with the pH drop method of measuring, but wasnt sure of it because pH is logarithmic and ppm is linear... I've taken organic chem courses and am familiar with equilibrium and whatnot so it seems plausible, but still not certain. This method must have an operating range of pH's? My GH is around 8 degrees, and kH around 3. Will adding co2 drop the measured kH?

As mentioned, I'm running 2 2L bottles, and intended on adding a 3rd once I finish my bottle of juice. Obviously I dont need to use the full volume of my bottles however.

[charlie]

Yes. I'd heard from other sources that it was _impossible_ to overdose CO2 with DIY, and was running 2 2L bottles of CO2. When my fishes started dying, I realized "Duh, of course it's possible to overdose with DIY" - just depends on the total number of liters you have feeding how many gallons. To take an extreme example (which is thoroughly unrealistic), imagine using 30 2L bottles to feed the co2 on a 10g tank... clearly this would be enough to overdose the CO2 if it's all getting diffused. I'm using 2L bottles because that is what is most accessible to me.

My fishes have been doing fine for months now, and I'm starting to add more and more plants (the last one was added about a week ago). Aside from the addition of plants, nothing else has been changed in the past month.

I found the efficiency of the reactor to be superb; my only problem with it is the space it takes up in the tank. As it is I dislike having the heater and filter intake sticking into the tank, I'm going to try going with a system that diffuses the co2 into the water outside the tank and then gets pumped back in, but i'm not sure i'll be ahead with this since it'll mean another intake and output :p

My lighting is 2 24" t12 on a 12h cycles (i realize this is long, but I dont really have algae problems). This gives me 40W of t12, but since my tank is extra tall (24"x12"x24") the watts per gallon calculation should actually be done on 20g and not 30g. I've done extensive research on lighting, calculating the lux from my lighting, and the lux requirements for my surface area, and it works out to a medium range of light intensity. One tube is daylight, the other cool white.

Hmm... I was running my co2 though the night, and it was in the morning that i noticed the dead fishies; this might have been the main source of my problems 

My initial pH was over 8 (probably around 8.3) and with CO2 it was around 7.5. My only I'd read the site you referenced before, and was familiar with the pH drop method of measuring, but wasnt sure of it because pH is logarithmic and ppm is linear... I've taken organic chem courses and am familiar with equilibrium and whatnot so it seems plausible, but still not certain. This method must have an operating range of pH's? My GH is around 8 degrees, and kH around 3. Will adding co2 drop the measured kH?

As mentioned, I'm running 2 2L bottles, and intended on adding a 3rd once I finish my bottle of juice. Obviously I dont need to use the full volume of my bottles however.

A few things to consider- nowhere in my reply did i suggest it was impossible to OD DIY CO2, infact i made a point of stating -"If you are only doing DIY with the recommended mixture of sugar to yeast & 1 bottle as a generator for your 30 Gln . tank, i would highly doubt you are generating that much CO2 to cause that. ", i can tell you that i just acquired 20 juvie Cardinals, they are in a 20 gln. long tank that is injected with CO2 -approx 40 PPM via pressurized system & they are thriving.
(2)In general there is very limited ways of controlling DIY CO2 injection, the only ways i have tried to some degree of limited success is by adding a air stone at nights /lights out to help out gas some of the co2, the other was placing the bottles in a container of water & heating the water with a heater during my photo period & heater off a hr or 2 before my lights go off , this was done in conjunction with the air stone coming on when the heater went off.
(3) The suggestion of 1 litre bottles by me was a mistake , i meant to say 2L pop bottles, the proven standard of DIY generators.
Good luck

[Toss]

Yes you can OD CO2 and the effect is almost right away. You mentioned a couple days later. Usually with sugar/yeast DIY the bubble count should be stabilize after 6 hours and decreasing slowly after that.
I have an average needle valve on my pressurized system. One day right after I cleaned my filter I see my all my fish swimming close to the surface gasping for air. I have my CO2 tank right next to the filter and I guess I accidentally touch the knob of my needle valve and I got like 10-13 bubbles per second. I brought it back down to 3-4 bps and all the fish back to normal in about an hour time.
So my point is that the sign of CO2 overdose is pretty quick, almost right after a drastic change (increase) of CO2 injection to the water column.

I had done sugar/yeast DIY for at least a year. After doing some calculation on the cost of sugar and manpower, also the possibility of tank upgrade or addition, I decided to go pressurized

[Soeman]

I'm sorry Charlie, if I implied that _you_ stated overdosing is impossible with DIY co2 it was not intentional. I _have_ received such replies from others however.

Yes you can OD CO2 and the effect is almost right away. You mentioned a couple days later. Usually with sugar/yeast DIY the bubble count should be stabilize after 6 hours and decreasing slowly after that.

Perhaps my yeast is a bit old, but it takes about a day before my co2 really ramps up, and longer before it reaches max performance.

I really think my biggest problem was dosing co2 at night. if i turn off my powerhead diffuser the co2 will be released in big bubbles out the top... with my water level at the top where i keep it water flows across the surface as it comes out of my biowheel filter. Will this be sufficient to bring CO2 levels down at night?

[charlie]

I'm sorry Charlie, if I implied that _you_ stated overdosing is impossible with DIY co2 it was not intentional. I _have_ received such replies from others however.

Perhaps my yeast is a bit old, but it takes about a day before my co2 really ramps up, and longer before it reaches max performance.

I really think my biggest problem was dosing co2 at night. if i turn off my powerhead diffuser the co2 will be released in big bubbles out the top... with my water level at the top where i keep it water flows across the surface as it comes out of my biowheel filter. Will this be sufficient to bring CO2 levels down at night?

Hey Soeman, no worries, just wanted to make sure of where that suggestion was coming from , some folks apply  read theories willy nilly .

My suggestion is test your saturation level with your current 2 bottle rig via the 1 PH drop to get a decent reference point of what you have now before going 3 bottles.
Another observation from your last post which even further makes me doubtful of your 2 bottle rig over saturatiing, is the fact that you are using a bio wheel filter, they are notorious for out gassing CO2 even more so than a Aqua Clear, but anything is possible.
As i suggested earlier, a good vibrant air stone or power head turned on just before lights out, aimed slightly upward to break the water surface, will go a long way in ensuring your fish is safe from CO2 when the lights are off.
Regards

[Soeman]

Hmm... i just had another thought. My co2 powerhead pumps water down through a plastic container 'blocked' with filter floss, thus preventing co2 bubbles from escaping undisolved. After just 1 day the white floss started turning green (algae, no doubt). Is it possible that anaerobic bacteria started building up aswell and released toxic compounds into the tank?

P.S. I one of the posts it was suggested that yeast might have ended up in the tank... I have a co2 clarifier (jug with clean water at low level where co2 is pumped into, and with co2 being taken out near the top), and there was no cloudiness.