Co2 Issues at On Time

[Brian Murphy]

I'm gonna try and explain this as best I can so bear with me lol. I recently purchased an UP 3-way needle valve (Tri-regulator) and am using Co2 supermarket regulator. I have 2 outlets from the 3-way, one to an UP 16/22 Inline Atomizer and one to a glass diffuser under the filters inlet. I am using tubing from different companies so not sure if that can cause my problem or not or maybe the distance it has to travel or maybe the different bubble counters I'm using.
My problem is when the timer comes on 2 hours before lights on they dont both come on at the same rate that I fiddled to get them at the day before, so everyday basically, I'm trying to get them both giving the same rate as I set them at the day before. Could it be a dodgy needle valve or the different equipment leaning the Co2 to choose the path of least resistence? It is ok as soon as I set it but once it goes off and comes on again I'm back to square one.

 

[ian_m]

Your setup is probably not working due to the pressure differences required for a glass diffuser vs an inline diffuser. A glass diffuser will work at very low pressure, this is why only a glass diffuser can be used for yeast based systems, compared to say at least 2bar required for an inline diffuser. All the CO2 is taking the path of least resistance ie the glass diffuser. You may be able to adjust even rates for both ways, but it will be very sensitive as you are finding.

You solutions are:
- Make both diffusers identical, with same bubble counter and lengths of piping (and same depth in tank ?)
- Use two CO2 cylinders and regulators.

 

[*pagey*]

Ian is correct here, it is the pressure difference / chosing the path of least resistance. I would disconnect the glass diffuser and just use the inline diffuser (although the glass diffs do look good with miniscule bubbles).
What size is your tank? Is it essential they come on at the same rate? If they are sharing a bubble counter then the quantity of CO2 being input to your tank will still be the same.
You could try and reduce the length of tubing to the glass diff which would cause less resisitance than that going to the inline diff. Im sure I did an experiment like this at school, there is a formula for it somewhere.....?

 

[Iain Sutherland]

If each atomiser is running after the needle valves then 'path of least resistance' shouldnt make a difference. the needle valves regulate the amount of co2 being sent to each diffuser. If T'ing off from one line then yes this wont work.
Have you left it a while to see what happens as the inline diffusers can take 15 minutes to clear the water from inside its casing, ive always found that when first coming on then the bubble rate will be really high then really low while it clears after which it should settle to where you left it set. Same with the in tank diffuser.
Anything after the needle valves shouldnt make any difference. A picture of the set up would help diagnose.

 

[Brian Murphy]

It is the Atomizer that seems to be going ok when it comes on, not the glass diffuser so if the glass diffuser was 'the path of least resistence' then this is not the problem. I have a 4ft tank and the alps 2000 filters hosing is too wide to fit a atomizer on it without reducing flow so this was my least costly option of providing Co2 to both spray bars without going down the DIY reactor route (not very handy or too lazy).