T5 Lighting affecting mains supply

[Colinlp]

I just bought some Arcadia T5 lighting and an ATC 300 external temperature controller. Both work well independently but when used at the same time the temperature reading drops by about 6 degrees C and the heaters come on until the tank temperature has risen accordingly. I suspect this is due to some sort of mains feedback, is there any kind of filter I can put in to try and stop this or any other ideas out there?

 

[Colinlp]

I tried the lighting in every socket in the house and as soon as it was switched on the temperature controller went screwy, by 15C this time. Has nobody else come across this before?

 

[Colinlp]

I asked the same question on a Hifi forum and got loads of suggestions. It turns out that it seems not to be mains feedback but EMI, I removed the sensor from the tank and put it in the sump and it looks normal now, going to keep a very close eye on it for a while to make sure. I hope this helps someone in the future.