I have been using liquid fert's for over 10 years. i use Thrive, iron, potassium, nitrogen, excel, phosphorus and advance.
I also use root tabs.
My plants seem to do very well.
I do not use co2, Lights on about 7 hrs a day
I dropped my I phone in my built in pool at the deep end, (when I first opened it up this year) it was down there a good 20 minutes @ 9' deep before I was able to get it oput. It was fine. I do have a Otter box cover on it though.