I would lower your photo period to at least 8, as for the algae try using hydrogen peroxide on the algae during water changes (worked for me) not sure why everything is randomly dieing off though, are you doing your water changes the same ? Same lights ? Same CO2 setup ?
Lights have changed considerably. I started off with one of the cheap amazon LED arrays (Nicrew), doubled it a couple weeks later, then finally got a Finnex when I realized how bad the cheap ones were. The CO2 has been much lower than it is now. Water changes are like 20% every week and a half although I'm not super regular with them (ammonia is very low).
That said, all the previous changes have been in place for about 2 weeks and I'm still seeing slow but tank-wide death. I'm at a loss. Good to know about the H2O2, I'll give it a shot. Not too concerned about the java moss, that stuff grows like a pest.
Well to start if you're only dosing Flourish, that's not enough. Spend $20 and buy a set of dry fertilizers to cover your micros and macros. You also probably have way too much light as the Planted+ should be plenty enough light for a 10g. Last but not least your co2 levels need a bump, 1 bps per 10 seconds is very little.
If it were me I'd tear it all out and start from scratch.
I'll look into the dry ferts and get some once I decide whether or not to tear everything out, but what strikes me as odd is that I'm not supporting a huge plant-mass so I assumed I'd be ok with Flourish and Amazonia substrate (at least for a while).
I'll also remove the extra lamp I have on there, you're probably right about the Finnex being enough.
The CO2 @ 1 bubble every 10 seconds is from a while ago, it's currently running at 1 bubble per second. Do I need to go higher? I've looked at the dKh vs pH charts for CO2 and it seems like I'm sitting in the right range... except for the part where everything is dead.