Hi all, This is my first post after using the site numerous times. I have just started my first own Hydro grow - 400 W HPS, 4 Pot System Clay Pebbles and Water Pump. Temps have been around 20-26C whilst I germinated the seeds and kept in a cupboard under a 125W CFL 20 hours on 4 off all seemed well with nice growth and on the transplant to the hydro set up im not sure if they have had a shock as they are now situated in a tent in the loft where temps at the mo are getting down to 7C and only upto 20C when light is on. The water is cold so I am waiting on delivery of a heater for the resovoir. Im wondering if the drooping in 2 our of the 4 could be caused by the shock in temp drops and the cold water streaming through the pebbles or the change in light power or can it be worse? It has just now had one full day cycle (20 on 4 off) am I being a bit too hastey or am I right to worry. I have a fifth plant still in the cupboard which I am keeping 'just in case' I am using plant magic hard water A & B 'grow' (I have the 'bloom' for when I put into flowering) and I have been using the PM Evolution Spray once a week as directed. I started off only using 1 or 2ml of both parts for first 2 weeks (bottle suggestion 4-5ml per litre I was 1-2ml per litre starting at one and increasing to 2) but started to notice a yellowing of bottom leaves so I increased it (to just under recommended level) for 3 week and seems to have done the job. I am using PH 6.0 water in the system. My colour indicatior will not allow me to go lower than a 6.0 reading. Pics attached from week 1 to 3 (as of last night) When checking halfway point today still a bit droopy. Plants 2 and 4 seem to be taking the transplant worst. (Last Pic) Also, Should I have the water pump running contiunously or only while the light is on? Also this isnt really a drip system its more of a constant stream into the pebbles cause by drilling holes into the hose and creating a block at the end of the hose this pressures the system up shooting the water across the pots and into various places but with water never touching the plants. Hopefully I have included enough info for you to imagine the set up. Nearly forgot, the strain is critical (7-8 weeks flower - not an auto-flower though), royal seeds (or something along those lines) from Amsterdam. Many thanks in advance.