Drooping, Spots forming on lower fans

This is my first grow, and it's been a pretty basic operation so far as I learn the basics. I made the mistake of using MG potting soil, but up until this point (2 full months into veg) it's been pretty consistent in terms of growth both vertically and in new undergrowth.

However, over the past week I've noticed some drooping (pic attached) and some yellow/brownish spotting on the lower fan leaves (pic attached). I've been super conservative on water, only watering once every 2-3 days, using the finger testing method. I had a lot (or so it seemed) of gnats early on, but they seem to have dissipated recently.

I recently added a little more light to hit the undergrowth as my previous set up was just hitting the top. Two 26w cfl's were added.

I'm using purified (reverse osmosis) drinking water at room temperature.

I've also noticed the smell lessening lately if that helps (at least the gf is happy w/ that).

I guess I'd like to know if doing a transplant into a recommended soil would be a good first step into trying to save the plant. If so, what's the best way to attempt this on a relatively large plant? Also, should I do a full soil flush before the transplant?

I know a PH test would give me a much better idea of what's wrong, but from what I've gathered on here, it takes some pretty solid equipment to accurately determine the PH. I was hoping doing a transplant into the right soil might help immediately while I acquire the necessary testing equipment for this growth and future attempts.

Finally, I've also read that root bound plants might have some of the qualities I'm describing. According to the full-plant pic provided, does the pot size look like it's enough for the plant?

Thanks a ton guys, seems like a great community and so far I haven't run across the usual assortment of folks that can make forums nasty places (know-it-alls, trolls, power-tripping mods).

 

Thanks for the quick reply GG - I was hoping you'd see this. Couple of quick related questions if you don't mind...

1. Should I have any concern using my hose to rinse all the soil off when it's getting pretty cold where I am in the <st1lace>Midwest</st1lace> and the water is probably going to be pretty cold, or am I overthinking?
<o> </o>
2. During the transplant, would I be able to see if the roots were bound at all in the last pot/soil? Also did you happen to take a look at the full-plant pic? Is the current pot big enough for the plant?
<o> </o>
3. Do I need to buy the $160 PH meter to test the water I'm giving it or is there a simpler method? (complete chemistry noob). Like I mentioned, I'm using purified drinking water as my tap water is pretty soft so I thought the purified drinking water would be a lot better.
<o> </o>
Thanks a ton!

 

Once again, thanks a ton. I've found a place not too far away that has Fox Farms products so I'll call in the morning to see if they have the Ocean Forest (I'm assuming that's the type). Should I add any perolite to the soil or just leave as is? Does transplanting into a different medium have a neg. effect?

Obviously I'll be as gentle as possible during the transplant, and I also got some superthrive for afterwards. Any other tips for such a large plant? Do I have to get ALL the old MG soil off the roots, or just a good amount.

I did buy a strip tester from Petsmart to test my water until I get a hold of a good meter.

Thanks!!!!