well, the bps are set @ 1bps, the morning the flow is stable, in the afternoon, i get 1.5 to 2 bps, the next morning, i get 1bps again... i though it was the temperature but she stay the sameWell, if it doesn't do what it is supposed to do - provide a stable, adjustable, low flow of CO2.
It would be helpful if you could be more specific what is the problem you want to address
yes if i understand well, needle valve is the heart of the co2 system, quality need to be high to avoid instability and algae ?Low end valves “float” which essentially means they cannot maintain the aperture you set it at. For instance you set it for one bubble per second. The next day it’s now 5 bubbles a second or barely a bubble every ten seconds, see what I’m getting at? Some people get away with the cheap stuff, others spend the money on a quality valve. They are very expensive nowadays
less than 30cm between the needle valve and the diffuser, does check valve can cause that kind of issue ?How much piping have you got between the various items ?
Having a long length of tubing between needle valve and diffuser is known to cause issues do to the tubing pressurising slowly, diffuser "burp injecting", depressurising the tubing, injection stopping until tube pressurises again and repeat. Try to get the needle valve as close as possible to injector. Make sure you are using proper CO2 rated tubing as well.
Yes, the check valve can also cause issues. Do you have a stainless steel CO2 resistant check valve? Normal check valves for air circuits can deteriorate due to the acidity of CO2. Have you checked for leaks in the CO2 pipes, bubble counter, and check valve? What type of diffuser are you using? Is it an inline diffuser? If yes, what is the regulated CO2 pressure you are using? Is the CO2 diffuser clean? Does this problem still happen if you use a different CO2 diffuser (for example in tank diffuser instead of inline diffuser)? In any case the problem you describe can be related to the needle valve - as others said, a quality needle valve that can keep its regulation can be quite expensive. But you need to describe your setup in more detail...less than 30cm between the needle valve and the diffuser, does check valve can cause that kind of issue ?
i have jbl special co2 black tube