Plants are not doing well! I think its the temp, please help!

Everything was good but then yellow tips came. The grow room is in the basement and the temp can get very cold. The reservoir temp is at 58 degrees when the light is on who knows how cold it get at night. I think this is a temp issue so I tapped in the the heat to warm up the room as well as putting a fish tank heater in it reservoir.

Here are some pictures. Please let me know what you think.








Me

A friend suggested that the its to much nutrients. I am going to flush it out then use 50% nutrients.

could be that..almost looks like spider mites though...check the back of the leaves for eggs...

I had the same problem with my plants. a few people told me it was nitrogen deficiency and someone told me it could be PH lockout... hopefully that helps.