Yes, more details would be useful.
28 Celsius is rather warm, most tropical fish and plants do better at 22 or 24.
What kind of suckermouth? Some can cause problems.
Pine cones can release resin, the best cones are Alder, various Alnus species, a very different kind of tree and cone, which are...
No problem keeping plants with those sorts of fish. You need to adjust yout ferts to allow for the amout of nitrogen in the fish's waste.
I would cut out the macro (NPK) completely to start with and see how the plants get on. You might need to go back to dosing small amounts of P and/or K if and...
I think Fiske is right, that's a long photoperiod. Also, the dawn and sunset may be giving four hours when the light is enough for algae to grow but too dim for your plants to benefit.
Reduce those times to 30mins, or 15 if your controller can do that.
Remove as much algae as you can...
it depends on what you're planning for your tank.
If you're going to inject CO2 the general rule is that you need the filter's claimed flow to be 10x tank volume per hour, to ensure good distribution of the CO2.
If not, you can go for a less powerful filter, or stick with high...