yeah changing the intakes/output would help if it's the throttling point
I realized last time I cleaned my 2217 I stuffed it with filter floss and I noticed the considerable loss of flow. I took out some floss and noticed the difference
Yes, unfortunately these intake/skimmers are like 40 bucks and mine is already past the point to return it. But oh well. It is the price of a mistake.
I'm not sure what time of day you did a water change, or what your water change schedule is like, but 6.8-7 seems high for a tank with Amazonia AND CO2. It could be that your seiryu stone is releasing more CO3 into the water than you realize, or maybe you're just changing with harder water. This might be the reason the Rotala "Butterfly" is struggling, since rotalas tend to like softer water and Butterfly is a particularly picky form. If it's not doing well, I'd say just go ahead and grab something like another ludwigia or limnophila that isn't as picky about soft water. Not worth putting your whole tank on hold for that one stem!
I doubt that your amanos are going after healthy AR. The AR is probably already struggling and they are just eating the dying leaves. I've never had them eat healthy plants before!
That's a good point, it makes sense. That could also be the reason why some of the Rotalas are not getting the colors that I expected them to get. Well, not much I can do about that because I am not planning on changing the hardscape, and tap water here in Florida, I would assume is harder than normal, since it comes mainly from very large underwater, cavernous aquifers (yes, we never run out of water here - suck on that California) so it might already come on the harder parameters. The butterfly, I could do without because it is just another stem, however the AR is hard to replace because there are not that many bushy middle-ground red plants available out there... So at the very least, I will just have to get used to the munched leaves. And yeah, I think you might be right because I've seen a lot of its leaves with deformities and some of them looking a bit dark and unhealthy, even before they have any holes in them.