Well, it never wasa true non CO2 method to start with

Excel and CO2 are not non CO2/Carbon enrichment methods.

No reason you cannot gain the beneiots with eI at low light, just do not need nearly that much dosing and in many cases, fish waste alone can add "enough", but you can still top off to be sure with light EI. It does no harm. Some enjoy scaring others that it might, but this is due to a lack of experience and other issues they have, not EI by itself.

I have used EI at 1 w/gal and at 1.5 w/gal for several years without any issues w high fish loading and with no fish load. Hard and soft water etc.

It was VERY EASY.

Now you may get away with less dosing and less water changes, there is much more wiggle room with less light in ANY and EVERY dosing routine for very obvious reasons.

But that is a matter of tweaking to your own taste for a routine(Say: I'm lazy and want to do 25% water changes once every 2 weeks instead).

But the 50% weekly still works super and makes things more stable in general if you add good CO2, Excel etc.

When I discuss non CO2, it does not imply Excel dosed tanks.

Nor does Diana nor anyone for that matter I know of.......
Yea, it's not CO2, but it is carbon enrichment........

Regards,
Tom Barr