1) C02 Controller 2) Heating

I am from Kuala Lumpur, Malaysia. Where the temperature would
be likely in the range of 32 - 34C.

I have a 200l tank. Duplaflex 300 heating cable with 2-3mm 
gravel. The heating cable being controlled by Duplastat 300.

Water at 4KH/5GH 6.8pH. pH being controlled by Dupla pH

Have ordered Dupla's dosing pump 3 days ago from Dupla's agent
in Singapore. Lighting consisted of Arcadia 150w MH Pendant
(UK product).

1) My C02 controller is very sensitive to the switching on/off
of the house flourescent tube. When the controller is
injecting C02 with the red LED on, and then someone switches
off a light, the C02 controller will follow suit. Have tried
to use voltage stabilizer on the controller this morning but
with no effect. Any idea?

2) Room temperature 30C. But we all know that aquatic plants
would best be in 27-28C. Would I be crazy to set the heater stat
at 31-32C so that a nutrient spring develop in the gravel?
Or should I just make do without UGH? Anyway now is the hottest
month in Malaysia. I suspected the room temperature to fall
in the region of 27-28 in a couple weeks time.