Well if you just need smaller scale solar like 5kw, hybrid type.
Nowadays it only costs about 22k.
However you won't be able to connect your whole house to the inverter.
Choose those power hungry device like aircond and fridge, they are usually the cause of high electric bill.

22k is include contractor work to install panel on the roof, pull wire to the inverter and connect the inverter to part of your house electrical supply.

This is not for selling back to TNB.

inverter only 5kw, run 2 aircond already hitting the limit.
Don't want to put too much stress on the inverter.

Btw this is for single phase supply house. if your house has 3 phase your need 3 phase inverter which is much more expensive!!!

200w for 8 hours = 1600wh

base on 3.5 sun hour you need 457watt of panel. Assuming 80% panel efficiency your will need 571watt of panel.

For energy storage of 1600wh using 12v battery, you will need 133ah.
Knowing lead acid only good for 50% discharge if you want the battery to last longer.
You will need 12v 300ah battery.
Add more capacity (panel and battery) to cater for consecutive cloudy days.

If you want to play hardcore then try lithium batteries. 

your 200w light is ac or dc light?

My hybrid inverter charger is 4kw only. I get 5kw panel so I could get more power when the sunlight is less optimal.
With cloudy klang valley weather, I seldom get optimal power output so put 25% more panel lor.

for 3 phase, there are two ways to do it.
1) Use a single 10kw 3 phase hybrid inverter. costs like 14k.
2) Use 3 unit of single phase 5kw hybrid inverter, costs about 12k. The inverters are linked somehow and got software to sync up the phase. but you will need much more space to put the solar panels for the 3 inverters...

rm22k include 4 x 12v 150ah battery. I am using 48v system.

TNB rm450 per month, means one month you use about 1000kwh, one day you use 33.3kwh.
A 5kw system at perfect condition can offset 17.5kwh per day. Which means your monthly consumption will reduce to 474kwh.
At 474kwh TNB bill will be Rm166.78. You can save rm283.22 per month, in a perfect world.

It will take you 77.6 months to ROI the rm22k you spend. Which is 6.5 years. 
BUT!!!
since you're using lead acid batteries, you need to change the battery on the 4th or 5th year so the ROI will be much longer.

PS: Lithium iron phosphate batteries, at 80% discharge rate, have a theoretical lifespan of 10 years. 

I'm not familiar with lead acid battery lifespan 
But I believe if you set DOD of 50% it should last longer than 500 cycles...

Plan to make a 12v system?

Depending on the type of panel voltage and your hydrophonic power consumption. Any decent controller (even the RM25 PWM controller) will store excess energy to the battery if your load is less than solar panel charge.

Example
Solar panel provide 1000w power
Your hydroponic pump only uses 100w
The controller will charge the battery with the remaining 900w(minus some conversion loss)

You will need a solar controller. Whether its pwm or mppt will depend on your panel voltage.

The voltage of the system depends on your hydrophonic pump and power requirement.
What is the estimated power for your hydrophonic? only pumps?