DC, please tell them what the pressure is into the PVC manifold so they don't accidentally hurt themselves.
*BOOM!* For the DIY-challenged, I'd go with a commercial manifold. I'm not saying about DC's DIY skill or techniques, etc... (In fact, I love all his DIY projects and make the HOB UV sterilizer too!), but I wouldn't trust a CO2 tank at 900psi feeding into a manifold I built with my own two hands.
The PR of the pvc I used is 450psi but that manifold is charged to less than 20psi. Charging any CO2 system over 30-40 psi is just plain stupid and inviting trouble IMO. 30 psi is more than sufficient to run a 5 port pvc manifold spanning 6 foot and I plan on connecting another 7 port manifold to this one for the other rack.
The old adages still holds true, if you don't know what it is, don't #$%^ with it. I have not made any of my DIY projects idiot proof and are posted for entertainment purposes only, try it at your own risk as they say and by all means protect yourself from your own stupidity. I tried commercial manifolds, they didnt work worth a #$%^ and helped me gas several hundred shrimp and fish. Different size tanks at different levels are very difficult to consistently inject CO2 unless you run it 24/7.....DC
During a visit to the mental asylum, a visitor asked the Director how do you determine whether or not a patient should be institutionalized.
"Well," said the Director, "we fill up a bathtub, then we offer a teaspoon, a teacup and a bucket to the patient and ask him or her to empty the bathtub."
"Oh, I understand," said the visitor. "A normal person would use the bucket because it's bigger than the spoon or the teacup."
"No." said the Director, "A normal person would pull the plug. Do you want a bed near the window?"