Mystery fish/shrimp deaths: Is it the C02?

[TheMacInnis]

Hi-

I have kept a 50g tank for years without issue. I decided to spin up a 10g tank as an experimental tank. I planted it, and after it cycled, I introduced fish and shrimp. All the fish except one have been fine, but the shrimp have ALL died. Three. Times. Most are dead within 24 hours. Some die after 48. But none survive past 48.

I have been trying a close eye on the pH, the KH, GH, etc., and have done very careful acclimation of the shrimp.

Tonight, after removing the carcasses of the six shrimp I introduced yesterday (sadface!), I started doing maintenance. Scrubbing algae, cleaning the C02 diffuser, etc... and when I reattached the diffuser and plugged in the solenoid valve...

... blam!

C02 BLASTED into the aquarium! Like a Sodastream! I panicked and yanked the diffuser out of the water immediately.

I am using a small C02 tank, and it appears that the tubing between the tank and the (separate) solenoid valve is building up pressure while the valve is closed. When the valve opens, that stored pressure (whenever the tubing equalizes with the tank, or, perhaps just whatever manages to leak out in the 15 or so hours it's off) comes out as quickly as it can.

Is it possible that this is the cause of the deaths of my shrimp? Are they being suffocated by a sudden C02 blast?

The tank is right next to my desk, and I feel like I would have noticed this happening each time the light comes on, but when I tried it again just now (having closed the valve for 20+ minutes to let the pressure rebuild), it did it again.

Thoughts?

Also, does anyone else have tubing BETWEEN the C02 tank and the solenoid valve? I'm now beginning to think this was a dumb mistake, although I'm not sure how else to connect the elements, since the tank doesn't have a valve that allows a direct connection as with my 50g.

Thanks!

 

[Fresh2o]

Sorry about the shrimp loss. I had poor success early on with shrimp and it may have been due to poor stock, an immature tank, and low minerals (calcium).
I believe if the buffering capacity is sufficient, the pH swings caused by the CO2 will be minimized. Conversely, low GH and/or KH can result in pH fluctuations.
From what you are saying, the solenoid is not connected directly to the CO2 tank? What is the size of the CO2 tank? What kind of connector is directly attached to the CO2 tank that connects to the tubing? What kind of tubing is being used? Is the regulator/pressure reducer connected to the CO2 tank? Pics might be helpful.
I'm using an Aquatek premium regulator which connects directly to a 24 oz paintball CO2 tank via a PB adaptor. Pressure is reduced to 20-30 PSI before going through the CO2 tubing. The PSI directly out of the tank is about 900. I cannot imagine any type of flexible tubing being able to handle that pressure (I could be wrong).


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