Passive CO2 bell question?

Ok so i made small fish tank 7 gallon that i have now decently populated with plants, 2 x anubia nana, 10 x dwarf sag, 1 x crypto ( dont know name), 5 x valisneria and hornworth ( some floating some barried in subtrate.
Its new tank build, today is 11 day since starting it and i experienced half of mine valisneria melting and some others melting also but after i replanted tank today i noticed that all plants that i was replanting actually had roots growing ( previously trimed when planted) and now grown maybe 1.5 cm in root lenght.
Plan is to add passive co2 diffuser by adding 300ml glass botlle upside down on back of tank and filling it with co2 to difuse slowly just to help plants in first month to get nice growth.
So i went out and bought small co2 bike pump simmilar to one in pic here( just ordered today should arrive on monday) and it comes with 2 x 6gr capsules.
Need to know if i do this do i risk adding to much co2 by filling it once a day when lights come on ( light are on timer 11 am to 7 pm) 8h cycle.
Also i read that this way there is no danger of killing fish as exchange is slow and as long as all co2 disperse while light are on its ok.
Is that true or not? And if anyone has experience with passive co2 how long wil it take for 300ml of co2 to exchange this way?
I know its not best way of doing it but i cant afford pressuriezed option right now and this way i can get some at least in tank litlle is better then none.

I use an inverted bottle in my tank you cannot add too much CO2 with the lights on or off. As to how long 300ml will last I am not sure. It probably depends on the tank size setup and other factors. As to the device you acquired you really can't control the flow of gas very well with it. So be very careful with the valve and turn it slowly As soon as gas starts flowing stop moving the valve and then turn it off quickly when the bottle is full.

Are you using a plant fertilizer. I normally recommend starting there before going to CO2.

StevenF said:

I use an inverted bottle in my tank you cannot add too much CO2 with the lights on or off. As to how long 300ml will last I am not sure. It probably depends on the tank size setup and other factors. As to the device you acquired you really can't control the flow of gas very well with it. So be very careful with the valve and turn it slowly As soon as gas starts flowing stop moving the valve and then turn it off quickly when the bottle is full.

Are you using a plant fertilizer. I normally recommend starting there before going to CO2.

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hello mate tnx for helping out
I use sera florena fertilizer just started with it one dose 6 days ago next dose is on monday
and i have control for co2 as it comes with hose for footbal inflating i squized it down with pliers allready tried to test in my bucket i use for water changes its no issue filling 300ml botle up 1 sec release is all it takes
Well now that i know i cant overdose co2 doing it im settting it up tommorow nothing to it but to do it tnx again

Well co2 bike pump is out of stock so i had to improvize today and its mineral water co2 lol

I had some success with a citric acid and bicarb setup. Can't remember the scientific term for it, but there's the two bottles that uses pressure/vacuum to draw more mixture in therefore create more co2. Only difficulty i had was ensuring no air leaks

mbsqw1d said:

I had some success with a citric acid and bicarb setup. Can't remember the scientific term for it, but there's the two bottles that uses pressure/vacuum to draw more mixture in therefore create more co2. Only difficulty i had was ensuring no air leaks

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yeah i looked into that build also yeast one but no need i think soda water is easy and no issue after i fill it up i close valve and i know it wont leak or explode on me ever as that botlle is build to take that preassure all day long so no issue with it i plan to do it only for month or so to get plant established

Should i for adding enough co2 to disolve in light cycle and fill it daily or i can fill more then plants use while light are on and there is lots left in disfuser bell??
300 ml took 12h to disolve completly and it stayed over nigh so just wondering maybe cut it to 150 and see if it disolves in light cycle and not leave it over night?

I am a Newby said:

Should i for adding enough co2 to disolve in light cycle and fill it daily or i can fill more then plants use while light are on and there is lots left in disfuser bell??
300 ml took 12h to disolve completly and it stayed over nigh so just wondering maybe cut it to 150 and see if it disolves in light cycle and not leave it over night?

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my CO2 tank is on a timer. it turns on for about 1 minute 4 times day. That way CO2 ispressent all day and night. The rate of CO2 dissolving in water is constant regardless of the lights turning honor off.