I did lower the lighting from 90% as I was getting Algae
I suspect the algae is coming from "everything" rather than just the lighting - it's fine to lower light intensity but then with the slower growth, fertilizer need will also decrease, also CO2 requirements ... for visual evidence of plant growth without excess of CO2 & fertilizers, watch the Tropica videos - while some are high filter turnover, high levels CO2, increased amounts of daily fertilizers, there are also many display tanks that run with stock tank lighting, internal filters & low CO2 ... it's really about finding the balance - which is the tricky bit
Water change every 3 days is more in the Tropica method, ADA suggests daily large water changes upon initial startup (ie new ADA soil) so if you're reducing the water change frequency, I'd also reduce the fertilizers (water change works as a "reset" to limit buildup of fertilizers) - you can still add daily if that suits, but be careful of amounts (ADA doses very lightly in Step 1).
If you're getting much melt, then increase to daily water changes, removing as much debris from healthy plant as possible - not so easy as you don't to disrupt plant rooting (this is where shrimp are much more adept than human hands
)
If you begin to see melt on the MC, try planting separate stems rather than "clumps"
How is the L brasiliensis doing? some suggest trimming back the emerse growth to stimulate new submerse leaves - just watch for algae sneaking in on the emerse leaf.
I believe you were intending to pick up a TDS meter - can you measure daily TDS? this may give you an indication of what's happening with your fertilizer additions.
CPD hiding in the fish shop tanks is not unusual, unless shop has a suitable tank with low lighting & loads of cover & in a quiet area & no other fish (so only net incursions are for CPD) & a large enough shoal ...