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... what are other good co2 regulators ...

You can build yourself a dual stage regulator. Here are some Victor models that I have.

Front Shot

Rear Shot

Green Leaf Aquariums offers one that is already built.

 

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is it cheaper to build the regulators yourself? What parts are needed and where do does one obtain them?

Those 3 Victor dual stage regulators that I built in the pictures above cost me $80 to $200 including shipping.

I purchased the regulators on eBay for $40 to $80 including shipping. The Victor chrome ones are mint condition used dual stage CO2 regulators from a hospital. The Victor brass one is a brand new 0781-3575 VTS253D-320 CO2 dual stage regulator. It has a list price of $380.77 at J&R. I sure wouldn't purchase one at that price for aquarium use, $80 isn't that bad though.

I purchased the stainless steel Swagelok SS-31RF2 metering valve for 99¢ plus shipping on eBay. My local Swagelok dealer's list price is $134.18. That was a good deal too.

I got the solenoids, Ideal metering valves, bubble counter, brass parts and non hardening pipe joint compound from SuMo, Green Leaf Aquariums, Clippard, a local plumbing supply and Lowe's. Rex Grigg sells these parts too.

They are very easy to build. Rex has a very good DIY article showing how to build them.

If you ever get a chance to use a dual stage regulator, I'm sure that you will like it.

Links
http://www.aquaticplantcentral.com/forumapc/equipment/59190-making-co2-system-2.html#post448267
http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club.html

GLA Victor dual stage regulator for sale
http://www.greenleafaquariums.com/co2-regulators/victor-dual-regulator.html

How do you like your Victor dual stage regulator?

I love it!
I have it set up with a DIY 3-way manifold using some cheap needle valves.
When I first noticed the initial high side pressure drop from 900 to 600 psi, I kept a close eye on the low side-(Initial setting of 5psi). 3 days later 400 psi and the low side didn't budge. It wasn't until the tank was near empty (200 psi), that I had to adjust the low side to get every bit of C02 possible. This Regulator is not only very precise, but it got me another week of C02 and NO END OF TANK DUMP.