High TDS after cleaning RO membrane

Hi,

I have BW-30 400 RO membrane which I am using for 2 years now, couple of months back I had to clean it because Permeate flow drops significantly, I used citric acid followed by caustic (NaOH) cleaning but after cleaning my permeate TDS are gone high to 80TDS while it was 30-35 TDS for whole previous use.

Can Anyone please guide me  how to restore it to original performance.

I shall be thankful.

Regards,
Mudabir Iqbal