How much did you spend on your pressurized CO2?

All I would need to do is buy a regulator, a needle valve and a tank, right? I can make my own diffusor.. is there anything other than that I would *need* to do this?

You'll need co2 resistant air line to hook everything up. If you cant see it and dont have to make any bends(its very stiff) then 8 cents/foot at lowes (if memory serves) is polyethylene tubbing. Teflon tape will be needed on threads like when screwing the reg to the tank. You'll probably also need a bubble counter to measure the flow. Selenoids arent required as some run thier co2 24/7 or feed it into a powered reactor and put the reactor pump on a timer so it goes off at night and co2 just bubbles to the surface. If you run 24/7 make sure to provide surface agitation at night! You should have some even if you dont run 24/7 but the need will probably be more so if you dont shut off the co2.
 
I was planning on keeping the way it was with an airpump on timer that goes on when my lights go out.

I might just buy something like this (http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=9935&Ne=40000&R=15686&N=2004+113219) and pick up a tank from another store. $95 isn't bad for everything you get. I think I definitely want a solenoid, it will save me some money in the long run not having to waste CO2 all night.. in fact, with one I could remove my air pump completely which would be nice
 
NEVER and I mean NEVER use Teflon tape on cylinder threads.

The first reason not to do so is that a CGA 320 valve doesn't seal on the threads. It's a flat faced seal and the threads only exist to provide mechanical force to flatten the washer.

The second reason not to do so is the Teflon tape can shred and if a tiny bit of that tape gets into the regulator body you can pretty much kiss it goodbye.
 
The first seal will come with most regulators. Then you should always get a new one when you get more CO2. The seal needs to be replaced every time you remove the regulator from the cylinder. Unless you have a permanent seal. Which I use on all my cylinders and would never go without.

Here's a picture of a couple of different permanent seals.

seal.jpg


This one is good if your cylinder has threads inside the nozzle and you own your cylinder.

seal1.jpg


This one works for just about everyone.
 
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