Misadventures in DIY C02

[meadeam]

A couple things I learned and hopefully can save someone else the trouble:

1. The more you fuss with the needle valve, the more you perpetuate the pressure differences between the bottles, and the more 'A' solution siphons to the 'B' solution, causing more reaction, which increases pressure, which means you need to mess with the needle valve... etc.   I built up nearly 4 bar of pressure trying to adjust the flow before I realized I was making it worse by constantly messing with the needle.
2. It's easier than I thought to reach CO2 saturation; I achieved a full 1 pH drop on the morning of my second day of C02 (I turned it off over night) and eventually had to take the diffuser out of the tank (29g) as my tetras were all clinging to the top surface of the water.  The drop checker started the morning blue eventually went all the way to greenish-yellow but the fish started stressing when it was green(they are fine now) and I should have been around 30ppm C02 according to pH drop at my kH.    

I've ordered a solenoid with a bubble counter and will use the magnetic valve to turn on/off so as to not have to mess with the needle valve constantly which causes an over-reaction. 

Edited November 9, 2021 by meadeam

[Fish Folk]

On 11/9/2021 at 4:48 PM, meadeam said:

A couple things I learned and hopefully can save someone else the trouble:

1. The more you fuss with the needle valve, the more you perpetuate the pressure differences between the bottles, and the more 'A' solution siphons to the 'B' solution, causing more reaction, which increases pressure, which means you need to mess with the needle valve... etc.   I built up nearly 4 bar of pressure trying to adjust the flow before I realized I was making it worse by constantly messing with the needle.
2. It's easier than I thought to reach CO2 saturation; I achieved a full 1 pH drop on the morning of my second day of C02 (I turned it off over night) and eventually had to take the diffuser out of the tank (29g) as my tetras were all clinging to the top surface of the water.  The drop checker started the morning blue eventually went all the way to greenish-yellow but the fish started stressing when it was green(they are fine now) and I should have been around 30ppm C02 according to pH drop at my kH.    

I've ordered a solenoid with a bubble counter and will use the magnetic valve to turn on/off so as to not have to mess with the needle valve constantly which causes an over-reaction. 

Your way is advanced fun DIY with CO2!

My son experimented with the age-old "natural release" of CO2 from an inverted turbidity column. CO2 was generated with Yeast + Sugar Water chemistry experiment. Guaranteed to eventually explode everywhere. Watch the beginning of this video to see how he set it up . . .

 

[meadeam]

The tank has been off C02 for 18hrs and had a 50% water change.  The drop checker is still green, and the fish are acting like there is low oxygen.  They seemed fine last night post water change.   I increased surface agitation by angling the spray bar a little more toward the surface, and will go get an air stone at lunchtime.  I really didn't think it would be so easy to gas fish with DIY C02.  I must have put a ton of it in!   I'm actually not sure if the DC ever returned to blue after the C02 had been turned off over night; it is so hard to see the difference, and I have a blue background on this particular tank 🤨

I will proceed very, very slowly on my next attempt.

[meadeam]

update: air stone running for a few hours, drop checker blue (really this time) and fish swimming normally.   pH back to normal.

I will start CO2 injection again tomorrow morning after running the air stone all night.  I will add CO2 slowly, periodically checking pH, and turn the air stone back on at lights out.  I'll order some timer outlets for the solenoid and air pump.