Hi,
thanks for your feedback.
seems like it is a combination of everything...
1. i dint wash sand (read from some comments in RC that washing removes all the goodies in the sand) changed filter sock 5 times...haiz..
2. too much prawn (50-50 on this coz the foaming started before i added prawn but i did add my expired reef nutrition actipods too before that). Removed most of the prawns that i can visually see except for 2.
i have removed the socks for now too. probably just going to let the tank run finish its natural cycle than do the water change. than on skimmer and add back socks and see how.