Light during 12/12-a question....could I beg some advice??

Well...I am 12 days into flowering, and things are looking really good, imo. I have not been going into the grow area during their dark times, but today I had to go in there and feel around for my wallet I left in there, and I decide to open the grow closet and take a smell.....and I noticed something that has obviously been happening since day one........my reservoir heater has a very faint reddish light that pulses on and off. It does this to indicate it is running. It goes on and off every 30 seconds. It is below the plants and very dim......but I am afraid it could create problems. The consensus is that it should be 300% dark during dark, but I also know that in the wild there is moonlight, which is way brighter than this little red light.
Anyway, I am going to try to figure out a way to eradicate this light, but I feel that keeping the res water at 75 is important as hell, too. Cold water causes plants to yellow.....I speak that from experience. So, my questions to any kind souls is would it be better to turn off the heater during the night and hope the water doesn't cool too much or to just let things keep going as they are, with the faint pulsing red light going on and off down below my plants. Any advice is greatly appreciated.

I cant see a red led light causing hermie problems, in my op i have 7 fire protection devices with each having a red led to show that the line is function normally.

If your unsure why not just put a peice of black electrical tape over the led so no light can get in the room from it,i keep meaning to do just that to my led shit but it's not high up on my things to do list so i always forget,one thing i can say with confidence is that in my op ive yet to experience any problems with the faint light from led's.

It really isnt a problem bro

cool......thanks guys....sets my mind at ease because since last night my colas have doubled in size, and are already thumb size at 12 days....so excited!!!!