Should I buy an airstone for use at night?

[STL_Cardinal]

Hi all, just wanted to seek some opinion if you think I need to purchase an airstone /w power head for use at night? I have a 75g heavily planted tank with pressurized CO2 that is only on during the day. I have 2 Rena canister filters with both spraybars located horizontally at the top of the tank with lots of surface agitation. Temperature is 85F and my stock list is below. All my fish are great eaters and currently show no signs of oxygen deprivation when I get up in the morning. Is it necessary to buy an airstone for use at night or is this overkill?

Fauna:
6 juvenile Stendker Discus (two 3", four 4")
2 juvenile angelfish
16 cardinal tetras
20 nerite snails
3 albino cories
2 harlequin rasboras
2 BN plecos
1 swordfish
2 platies

Thanks,
Paul

[H20M@N]

If your CO2 is only on during the day and your spray bars are agitating the surface, I see no need