Rain Water How Much Co2?

[Mulisha]

Hi guys

I had a problem last night in my 4x2x2 tank it has been set up for 12 months now and has been getting co2 all that time without once a putting a air stone in the tank. This morning i woke up and and started getting ready for work and i heard this fish plash at the top of the tank and when i looked closely i saw fish dead *Crys*. So i quickly get my air pump and add 2 air stones to the tank because soon as i looked closely in the tank all of what fish are left that gasping for air . Well i got out all my dead fish before i had to leave.
I lost 3 Congo Tetras, 2 Clown Loachs, 1 Discus, 1 15cm Pictus Catfish, 1 Pleco, 5 Black Widow Tetras.

I'm still hell dam annoyed at myself and why it happened?

The only thing i can put it down to is i live just out of town and i'm on tank water/rain water and i did a w/c last night at about 8:00pm i usually do them much earlier like at 5:00 - 6:00. What i think happened was our rain water tank doesn't really get disturbed before it gets pumped into our house so i reakon the rain water contains a heap of co2 and becuase i did the w/c at 8:00 and the lights turn off at 9:30 the plants couldn't use it all maybe and it left a high amount in the water still and over the night the plants are also releasing some so i'm not sure if this caused it or not but i'm really upset with how many fish i lost. I started out with 5 Red Turks from Rod Lewis about 6 months ago and now only have 3 left so it's not looking good.

What do you guys think i should do on a perment basis to fix this problem run a air stone at night (Every night) and put it on a timer so it turns off in the day? What about my water do you think it contains this amount of co2 to cause this problem? I really have no idea and still frustrated.....

Cheers guys for any help *sigh*

Rick.

 

[voo]

Why dont you get a KH test kit, and pH and test the water in the tank and rain water you are putting in. Rain water could also be acidic, depending on the polltion in your area.
Are you sure the water in our tank isnt polluted? Nothing can fall in it and die?

I'd reccommend leaving an air stone going through the night, that's if your CO2 is going through the night also.

 

[Mulisha]

I add co2 of a day time (When the lights are on) then a shut off solinode will turn the co2 off as the lights turn off.

 

[Bignose]

There is no reason the rainwater would hold extra CO2 than would be dictated by a natural tend toward equilibrium. All water holds a certain amount of CO2 in solution, which is called the equilibrium point. If there is less CO2 dissolved in the water than the equilibrium point, CO2 from the atmospere will enter the water. If there is more CO2 in the water than the equilibrium point, the water will give up CO2 to air.

This equilibrium point can shift, it would be a strong function of temperature for instance. The shift in equilibrium is a very weak function of the other minerals dissolved in the water. That is, rainwater will have other things dissoved in it than your tap, but I would suspect that the eqiulibrium point is only changed by a few tenths of a percentage. A degree change in temperature would probably change the equilbirium point by a full percentage point or two, by comparison.

So, in synopsis, rainwater does not hold any extra CO2 than regualr water, and I really doubt that was the problem. Not only that, but if there was lots of extra CO2, the movement of the water around the tank would have released it back into the atmosphere (again, always tending towards equilibrium) rather quickly (30 minutes to maybe an hour) and the same CO2 levels you always had should have returned.

 

[Mulisha]

Thanks for explaining that becuase i have a co2 system on my tank i have no filter outlets to break the surface of the water. If you do have experence with infecting co2 putting a air stone in the tank at night will it take long my tank to get to a okay level of co2 for the plants to start thriving again or will stripping the tank of any co2 of a night time and when the lights are on and the tank starts to get injected with take ages for those levels start to get to a good level for plant growth?

Thanks mate

Cheers

Rick.

 

[The-Raven]

rain would not affect oxygen levels in the tank.... and if you've been injecting co2 but have not been adding regular air or have surface disturbances to allow oxygen transfer, that's what caused your fish to 'suffocate'

 

[Tokis-Phoenix]

I would also test your tank for ammonia, nitrites and nitrates- ammonia for example in the water can make the fish gasp at the surface. The warmer the water is, the less disolved oxygen there is, so if your tank temp is very warm, that can also lead to a shortage of oxygen in the water.
You are injecting your tank with Co2 so your plants "can thrive again", but the reason why your plants are not doing well is often more likely down to other factors like lighting or the type of plants they are, i would check out the plant section of the forum to figure out what is ailing your plants as the Co2 may be unesarsary particually if it is other factors as to why they are not thriving.