No, me neither. One more level of complication I can do without. I too have some degree of surface agitation and CO2 goes off 4-5 hours before lights out. High(ish) filter throughput helps with all this as well.
I always had an air pump on my tank as the DIY CO2 that run 24/7 did affect the fish, now that I have pressurised I was afraid not to turn it on so I have it come on at lights out for about 3 hours and then goes off. Seems to be working fine with everything so I am going to leave it like that and I am sure the fish appreciate it
I don't keep Discus (my shrimp wouldn't thank me for adding Discus. lol), but I don't use an air pump either, they are too darn noisy! I just make sure that I have enough surface agitation to keep the CO2 levels from getting to high at night, and I use DIY CO2 running 24/7. I do sometimes have to move the suplementary (to my external) Fluval 2 filter higher in my tank to create more agitation, usually after changing the mix in 1 of the 2 bottles as there tends to be a spike in output at first.
Have you considered a small powerhead, perhaps with a venturi, set to come on at night instead? Much quieter and will help with circulation in your tank. They also don't have diaphragms in them that need replacing regularly.