CFL Autoflower grow; HELP

Hey everyone I'm new to this whole growing thing, but am running into a few difficulties while growing. I'm doing a small DIY DWC grow two 19L tubs with three plants two airstones. I'm using a modified(smaller portions) Lucas Formula GH system to feed them. My problems are as such; First, as seen in the pictures small burn marks that started out as little red dots all over the leaves, that is just on the one plant. Second these things don't seem to want to flower! I germed the seeds on the 7th of July I would figure the little buggers should be flowering by now but I see no sign of it!

One... do you have a PPM/EC meter?
Need to check your nute levels, maybe bring them down a bit.
Also.. with nutes have you changed over to bloom nutes?
What is your light schedule?

I do not have a PPM/EC Meter, only a pH meter, and in my reading of the lucas formula it states to use the same ratio the whole way through, I'm using slightly less than one third regular strength the lucas formula so I hope its not overfert. And I've been using 24/0 as I thought you could do for autoflowers, should I switch to another ratio?

keep your ph in the yellow and switch to 16 on 8 off, 12/12 or i personally like the 11-10 on and 13-14 off they seem to thrive during the down time and like to have some rest. you will notice the difference also even when its an auto flower it wont flower till the plant reaches its maturity rate at around 4 weeks or so even in an auto flower. after trying all these i like to go 12/12 from the get go with an auto flower. but the other schedule i mentioned helps veg a little more also some plants need that extra hour or two more of dark than light to kick em into flower! just try em all.

Yeah pH has been a problem with these things always seems to want to shoot way up. I have to adjust it all the time, I'll try to be more on top of it now though. And I'm gonna change the light cycle to something less around a 14/10 perhaps.

Usually takes 4 weeks for auto flowering. I also woulden't even change the light cycle, I would still run 18/6

start phing your tap water after adding your nutes let it sit for about 1 hr then test it and adjust because nutes makes ph go down as well. so ph your water after adding the nutes and you should maintain better. i too am growing in a small dwc bubbler tote 4 gallons with only 2 gals of water before coming with in 1/4" of bottom of basket.we have to stay more active with ours due to the fact theres less water present and also we will not have to go full strength in less water we can get results with starting at 1/8-1/4 strength then 1/2 then 3/4 then 1 tsp is all i use with such a small bubbler any much more and burn occurs for me! also i add ph'd tap thats sit out over 24 hrs for chlorine disapation and after adding almost 2 gallons of regular ph'd water when it gets low over time then i start adding gallons with nutes again till those 2 are gone then water again till the plain 2 gallons are spent this way i dont have to change it out as much.

Hi guys new question here, they started flowering now, looking good. But I went and bought a fan and carbon filter, just wondering how to set it up, I got a 435 cfm fan. The man at the store said to put the filter in the tent then the ducting (8 ft)then the fan on the outside. I was wondering if I could simply run the ducting in then put fan & filter on the other end of the ducting outside. He seemed to think this wasn't a good idea as it would make the air pass through the filter too quickly or something. Thanks for any help!

Anyone please?