I see some older leaves with GSA, new growth looks fine. A few rounds of trimming should remove the older leaves and GSA on them.
Generally I view it as CO2 and/or low PO4.
Thank's Tom, i will try to correct the dosing of the CO2(again) and increase PO4 and check results.
There are some GSA and the stuff on the leaf tips looks like young red algaes, obvisously BBAs.
the plant is just filled with old and new leaves. it just needs proper trimming then it would surely going to be fine.