We have been using Gravity Gray from Lowe's, any lightish gray would work honestly.

@Calvin LinThe true gravity of the crisis did not hit until mid March.

Franklinton has been seeing lots of developments like the completion of Gravity Phase 1 and with phases 2 and 3 on the way.

The building originally had gravity fed ducts which were all torn out. 

Time heals all wounds :-) Ya pay for it now or ya pay for it later, but gravity works and real estate is all about how gravity works.

I am the reason there is gravity on this planet.

General note ... there are dozens - maybe hundreds - of different on-site wastewater system system types, from basic "conventional" septic systems with a septic tank and gravity driven leach lines to complete package treatment systems (like a miniature municipal wastewater treatment plant).

Franklinton has been seeing lots of developments like the completion of Gravity Phase 1 and phases 2 and 3 on the way.

If it's a gravity feeder, such as the rear tray of a canon, it matters much less.

Sure, but it is about as useful as complaining that gravity prevents us all from flapping our arms real fast and flying like a bird.