Bigger the diffuer, the more they cost and the more CO2
you can pump through them (typically).
For finding a source to fill canisters, post a question or a help wanted ad on social media / local groups for a more localized answer.
Dual stage is not required, but they cut down on the risk of "end of tank dumps" where a single stage regulator can allow massive amounts of CO2
to be uncontrollably let go as the last of the liquid CO2
turns to gasn(nearing empty).
DIY is basically building everything on your own, regulator, solenoid, manifolds and needle valves.
Most quality regulators come with a solenoid that is cut for the job.
As to bubble counters, anything larger than a 25 gallon tank and they are for reference only. Tanks larger than 25 gallons are going to require so much CO2
that counting bubbles is impossible. My 25 gallon tank was well over 4 bubbles per second (uncountable) I had to use a metronome's beats per minute set to match the bubbles entering my reactor and dividing by 60 seconds to estimate my bubbles per second.
Drop checkers and pH drop are better for larger tanks. Drop checker for visual reference, and pH drop to moniter CO2
usage. A Dwyer flor meter would be a nice addition to fine tune and measure CO2
usage. RMA-151-SSV for medium sized tanks or RMA-150-SSV for larger tanks is whats usually used. You will need the correct adapter to go from a threaded connection to a barbed connection for the CO2
Aa for pH drop, a pH pen from amazon is an affordable way to more accurately measure pH (so long as it come with calibration fluid and is calibrated every so often). a Ph controller is "best" when using the pH drop method. Also, pH drop in a tank with active soils such as ADA or Tropica soil is less effective as the water is stripped of kH
and has a buffered acidic pH to start with. The pH drop method is best used on non-buffering substrates:
is dropping the pH of the tank water a full 1.0 – 1.2. To do this, measure the pH of tank water with no CO2
dissolved in it, and then measure again 2-3 hours after CO2
has been running. Ensure the drop in pH is a full 1.0-1.2. If the drop is not there yet, slowly up CO2
over a few weeks until at least a 1.0 drop is achieved, and watch fish / livestock carefully. Adjust CO2
down if you notice fish gasping at the surface and consider running an airstone at night when pushing a 1.2 or greater drop. For example, a tank water pH of 7.5 with no CO2
dissolved in it, should reach a pH of 6.5 – 6.3 for CO2
to really shine, and for maximum plant health.
Consistency in CO2
levels is key to plant health. Keep CO2
levels as stable as possible once a desirable level has been reached during the entirety of the photoperiod.