Are all CO2 regulators usable for the aquarium?

Actually I think most sold for aquariums are the least desirable (there are good ones, but I mean the cheaper ones). The JBJ all in one combo (in your last link) has served me well for a couple years now and is probably the cheapest I'd go.

However if you want to put your own system together (like I am doing on my current project) the reg in your first link can be found cheaper at beveragefactory.com , atleast it looks the same as the micromatic regulator that is at least $10 cheaper there if memory serves (cant check since that site is blocked on my work computer). The only thing is it is setup for 3/8" hose so youll need to either replace the fitting or use an adapter at some point. I've got it now but havent finished setting it up so I cant tell you how it performs but I amagine it should be a great reg.

Most any CO2 regulator can be adapted for aquarium use.

Some are better than others. Most all the Chinese built all-in-one units are a crap shoot.

Some regulator bodies are better than others. I personally won't use anything but a Cornelius body.

And you will need a few other parts to use a beer regulator with an aquarium.

For someone new to CO2 is it worth it to go for the PH sensor on the solenoid? I would rather not spend the money on something I can test myself, but I don't want to get myself into trouble. I do test my water regularly and would be willing to invest any time needed to test the ph myself. What do you think?

IMHO no. It's just one more thing in the tank. One more thing to check and maintain. And you will need to replace the probe every so often.

Failure to maintain or replace the probe can lead to catastrophic problems.

A probe can work but yes you do need to calibrate it and will need to replace it at some point. In terms of catastrophic problems, I use a drop checker also as a quick verification that I'm not throwing too much CO2 into the tank. Makes it easy to just walk by the tank and see 'green' (good CO2).

Course, I'm going through 10lb tanks way too quickly so I may be talking to Rex about a new regulator, perma seal, etc. :hihi: