1) Changing water - I am staying in Jurong (West), is there any LFS around the West, which I can easily purchase pre-make Seawater.
Or, is there any Brand of Sea Salt easy to mix/dilute?
I remember during last time buying Seawater from the LFS in West Coast, but notice is no longer there.
I think Henry at Marine Life does sell SW. Can check him up in our sponsors.
2) Light - I notice LED Light are getting popular and easy. Consider my above Set up, what LED Light is suitable?
If you are keeping Anemone, you need strong light. LED is suitable, do consider the ones that our sponsors currently market, think majority of them would fit your needs.
3) Skimmer - is Tunze 9002 is ok for a 1.5 FT Cube Tank (approx: 72 ltrs) and Sump Tank (approx: 40 ltrs).
Think 9002 is good enough for you, although you can consider other skimmers which could clean out more junk. For example, I love my MCE600
4) Live Sand - any recomendation and advise?
depends on your budget. Not a must have, but many consider good to have.
5) Chiller - I still have this Artica DB50 (1/15hp) with me, it is ok for 1.5 FT Cube Tank?
How old is it? When was it last serviced? You might need to get it serviced and see if it is in good condition. 1/15 should be just nice for 1.5 cube.
6) General Maintenance - beside weekly water change, what supplement/elements do I has to take note?
For now, just concentrate on water changes. They should replenish your elements.
Would advice against keeping tube worms for the time being as they require almost constant feeding.