Hi Newtothis,
I'm a newb also. I have an Aquatek regulator that I bought off ebay. I am happy with it but as a newb I'm probably not smart enough to know the differences between various regulators.
I have one suggestion on the regulator you are looking at. Verify that it has a pressure relief valve. Mine came with it, but that pic is a little different than what I remember. When I get home tonight, I'll post a pic of mine with the pressure relief valve. IMO, you're nuts if you don't have a pressure relief valve. Properly filled the tank will start at 800 lbs of pressure. If it overheats (don't panic, it takes a lot to overheat a tank) it will explode without a pressure relief valve. With a pressure relief valve, it just gases off.
My regulator also came with a bubble counter.
To digress on tank safety, the test I saw was on the tv show, Mythbusters. They put a filled CO2 tank with a pressure relief valve in a fire. After about 5 minutes, the valve opened and the gas bled out. The tank didn't move. (Some say the become a projectile. That is wrong with what I saw.) They then tested a CO2 tank without a pressure relief valve. After 10 or so minutes in the fire, it exploded, not ruptured, exploded. So don't be frightened of the tank but treat it carefully.
Back on topic, I bought a new tank off ebay from mirageimage. One listing is here
NEW 5 lb CO2 Aluminum Cylinder W/Valve co 2 tank 5lb - eBay (item 140317364793 end time May-03-09 05:19:05 PDT). Cost was about $60 with shipping included. I got it filled for $10 at a local fire extinguisher shop. Some use welding shops but they aren't always setup to refill tanks.
I considered a PH controller but decided it was unnecessary, expecially since the regulator came with a solenoid. I've got mine plugged into a timer that turns it on and off with the light.
You will need a diffuser or a reactor. I went with a home built reactor on the outflow of my canister filter. Tom has instructions for making one in a thread but I don't have time to look for it right now. If you with a reactor, note that it is advisable to have the water come into the top and out through the bottom. I've tried it both ways and feel that the CO2 absorption is better with water in through the top. The bubbles coming into the tank are much smaller and disburse much further and lower into the aquarium. Not a scientific measurement, just my experience.
A dropchecker is usually recommended to verify CO2 levels in the water. I have one but I'm not using it because I bungled the 4dkh reference solution for it. Without a working drop checker, I started off at a low bubble rate of 1 per second, then slowly increased it over several days watching the fish and plants closely. When the fish started to hover at the surface gasping for breath , I backed it down slowly until the fish began swimming normally again. I wound up at about 2 bubbles per second. My plants are doing well and are pearling before the lights go off at night.
You will definitely need to dose macro and micro nutrients with the CO2 so read up on that. In my experience, the recommendations are guidelines, not hard rules. In my case, I dose half the recommended nitrogen in my CO2 tank and am still getting nitrate readings of 20. I think I need to up either my P or K as I am getting just a little GSA but I haven't figured that out yet.
I didn't notice your lighting or tank size as those are part of the equation.
I gotta get back to work now.
HTH. Good luck.
Greg
