Bubblegum + OG Kush Autos

I'm reaching day 12 and these girls seem as though they have not moved at all.... This is my 3rd grow and I would like to think that I'm learning something each and every time. I have made this my hobby and it's become my obsession. My last 2 grows were much faster. Growing in basically the same conditions, accept not PH ing my water at all, buying my coco mix solely from the grow shop .This time I mixed the medium myself from coco coir blocks from a plant shop and perlite. My wife has been crapping on about expenses so I tried to cut some corners without trying to hurt the grow. Purchased a cheap PH meter and TDC meter to measure the ppm off ebay and have been PH'ing my solution to 6 to 6.5. Also started the grow in 5 gallon pots, and had some other photoperiod seeds starting in paper cups at the same time. The seeds in the paper cup seem to be having the same problem with the slow growth. Also only watering about 100ml every day or two depending on the conditions. I need this run finsihed before December as my wifes family are visiting and it all needs to be packed down ;) Seriously considering soil on the next grow or DWC. Dwc particularly seems to be getting some very fast results. Update: Thank you so much to all those who have reached out with your help on this one. I have now set the PH to 5.7 and upped the nutrient mix to 280ppm, I'm hoping that will help. The light I'm using is a Viperspectra TC900 LED running 400 true watts but apparently replaces a 1000watt HPS. Not sure how true exactly that is. Apparently full spectrum. 4ft x 4ft tent is running a 260watt grow candy tent heater, I run it with my vivosun thermostat. Since turning up the light spectrum recently into full veg the tent has been running hotter, keep in mind my carbon exhaust filter only runs once every hr to keep the hot air from the heater in. I feel since ive set the thermostat to 23 celcius and the carbon filter runs so infrequently (with speed controller) the tent feels bit too hot. Still will give it a try for a while. Will also use my heat matt under 4 x of the 3 gallon pots to see if I can stimulate faster root growth on some of these ladies (They are a mix of 4/5 gallons) I'm tempted to run the light cycle to 24 on, but will make these changes for now.