I only use RO water and add maybe 1/4 as much calmag as what it says on the bottle but still use it. I also add some epsom here and there especially later in flower. The sulphur in it is the 'secret ingredient' in most bloom booster formulas.
You can't get too much light from shop light and the tops of the plants should almost be touching the tubes for best results. I took 4 - 4ft T-12 shop lights apart 20 years ago and mounted the connectors at 2" centres on a piece of plywood. I put the ballasts on the back side of it. Each power cord on them has a quick connect so I can run them in pairs up to 8. On a trip to the dump a few months ago I found some ballasts that are for running 4- 4ft T-8s so I bought 8 LED tubes at Costco for $60 and will rewire the light to use them. Same amount of light but only 14w each instead of 40w so big saving on power at 30¢/kwh. Wife uses it to start her tomatoes etc for her garden.
Pretty sure this won't pass inspection but it works. I've since removed the fan and dimmer as it wasn't really doing shit.
View attachment 5149824
Covered the plywood with tinfoil after this pic so it gets more light to the plants. Some old tubes just for testing after adding the 7th and 8th tubes a couple years ago. Only had 6 for a lot of years. One ballast died so good time to upgrade.
View attachment 5149825
My DIY LED light is a lot prettier and grows plants pretty well too.
View attachment 5149835
View attachment 5149836
View attachment 5149837

[/QUOTE
Wow thanks for sharing those photos. I will try some epsom salt and get back to you next week. I will also get me a new EC/PPM meter and get you some readings.