Dwc/400watt

[Cali]

Decided I will try to share my progress weekly so any dwc experts feel free to give me any tips advice whatever. I’m just learning this is my 3rd dwc and 1st time doing two plants at the same time. My girls sprouted on the 26th and today marks The beginning of week 3 I believe? Also first time growing with a 400 watt hps. My previous grows were with a 150 than did a couple with two 150’s hps but decided to go a bit bigger for denser and bigger colas/ yield. Question I have a 600 watt hps bulb I want to dim down to 400, do I start the bulb at 600 then dim down or start it at 400 watt? Also my water from my sink is 195 ppm should I be adding cal:mag to my water? I did at half strength plus nutrients and it goes up to 540 I feel it’s a lot for second week? Here are some pics to me it looks a bit pale and the reason I added cal/mag on second week is because it looked like it needed it judging by the leaf stains but I also read that those yellow marks can be caused by ph fluctuation? Which reminds me I have to ph down because when I test my ph is high like 8.0 will my ph down drive up the ppm?

[Toker1]

You can start at 400, but I recommend getting a 400w bulb in this case. Especially if you are using a bulb specifically designed for plants. Otherwise you will alter the spectrum by decreasing the wattage. And MH bulbs deteriorate quickly when dimmed. HPS to but not as badly as MH does.
Tap water normally doesn’t need cal mag. RO water does. So depends on your source.
A PH of 8 is very high. I never let mine go above 6.5. I find it takes a few gallons of water 3-4 days and the PH is right back up there again after an adjustment.
Yes, adding PH up and/or PH down will drive up the PPMs.
How do you plant to keep the water cool with this new light upgrade? 1 watt = 3.4 BTU you were dealing with 510 BTU on your 150 w. Now you will be experiencing 1360 BTU on your 400. Major difference.

[Cali]

Toker1 Thanks for your reply. I have an exhaust set up for it as recommended in the GWE tutorial. As for the water I’ll be using frozen water bottles. Also I’m growing now because the weather is supposed to be cooling off here in southern Cali. Yeah I will be buying a 400 watt bulb but since I have a 600 watt for free I wanted to try it out while I get the 400 bulb.

[Toker1]

So you want to start the veg cycle with the MH bulb. In fact I use that MH more than HPS. The blue light is great until week 2-3 of flower. Really controls the stretching and stacks nodes to make fat buds. I use HPS mid flower and then back to MH for the last 2 weeks. This helps with tric production.
Make sure to keep extra frozen water bottles in the freezer, I had to switch mine out 2-3 times per day.
A water chiller is way more efficient, but costs $$$. Water bottles that are frozen are a good alternative, but lots of work if you have many buckets.
Cool weather is coming to CA! This is when I switch from soil (grown in the summer times) to DWC (grown in the winter times). This is how I do it to avoid all that costly equipment.