1/2 through bloom, tip burn possible calc. def.

First, I have a grow log in my signature for this current grow.

What is your experience level? (first timer, novice, experienced...)
Novice.
What type of hydro set-up are you running?
Ebb and Flow
Your Equipment:
A) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's) T5 Flourescents, 40k lumin main ballast, 20k lumin side ballast (at 45degree angle)
B) Distance from tops? 3-5 inchs
C) Reflector type? (cool tube set-up, bat wing, enclosed reflector, bare bulb...) ballast
D) What are the bulb wattages, kelvin ratings, and schedule? refer to Q. A
E) Is there a consistent fresh air supply? Yes
F) Do you have an exhaust fan and a circulation fan? Yes
G) Size of reservoir? 40 gallons
H) What medium if applicable. 1" rockwool cube from seed, 2 gal. bag in geolite

Your nutrients and water:
I) If using rockwoll for clones or seedlings, did you rinse the cubes well, with properly ph'd water? soaked in 5.5 ph with 1/4 strength bloom for 24 hours
J) Source of water. (tap or filtered) What's it's ph? tap, 7.0
K) Specific brand and N-P-K ratio for each bottle. List dosages (quantity per gallon) and current feeding schedule. Ionic Bloom/Grow 4tsp./gal and Ionic Boost with 3/4tsp./gal, and Liquid Karma at 2tsp./gal
L) What is the ec/ppm of your unadjusted tap (or filtered) water? 300ppm
M) What is the ec/ppm of your nutrient solution?
N) What is the temperature of your nutrient solution? (reservoir high and low temps) 67 degree low, 78 degree high
O) Does your ec/ppm show a rise or fall when you do your daily PPM check? rise
P) Does the ph fluctuate? after water change next day ph usually goes up a couple tenths of a point and after I nock it down it stays the same ph for the rest of the week
Q) Do you foliar feed? If so, with what, how often, and at what time do you
spray? (Just after lights come on, just before they go out...) I do not foliar feed
R) How often do you replace reservoir water/nutes? What does it look like before changes? (clear, foamy, green, brown...) every week, light brown, starts out really dark

Your growroom:
S) What size of closet, room or hut? hut
T) What are the temps and humidity levels while lights are on? ...With lights off? 50% humidity day and night, temps are 68 at night mid to high 70's during the day
U) Have you seen signs of insects in the growroom? no
V) Are the roots long and white, or brown and slimy? I can't tell, the ones I can see are dark brown but I am using Liquid Karma and it stains the roots dark brown like that
Your strain:
W) What strain are you growing? (Indica dominate or Sativa dom?) Its a white widow x blueberry hybrid, so 50/50 cross from dynafem called Blue Widow
X) From seeds or clones? Seed
Y) Is this an autoflower strain? No

I'd like to clarify that I'm using half strength Ionic Bloom (2tsp./gal) and full strength Liquid Karma (2tsp./gal) and about half strength Ionic Boost (0.5tsp./gal). My ppm sits around [email protected] immediatly after a fresh water change. I didn't want to lower the amount of nutes I was using in fear of not providing enough beneficial nutes to the plant. At the moment I'm screwed on getting an R/O filter but I'm working on it. Here are some various pictures of my problems. I've lost most of my larger fan leaves already which I was concerend but thought may have just been normal loss however now I'm seeing what looks to be tip burn on the majority of leaves and as you can see on the lower ones some rust spots and yellowing of the leaves and it seems to be creeping up the plant from my estimation. One of the pics you can see some dead leaves and most yellow leaves and a smaller undeveloped bud...that is the lowest branch node on the plant, the other one that is the lowest is alos very undeveloped but hasn't died off and turned as yellow as the one I took a picture of. So far my buds seem to be doing just fine aside from the tip burn on the leaves but I'm afraid its only going to get worse and severly affect my yield. I just don't know what to do at this point

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bump

First off what conversion does your meter use? .5, .64 or .7. All I can say is maybe your water is screwed 300 ppm is high for tap water. mine comes out at 125 ppm. also why did you soak the cubes in 1/4 strength bloom? i could maybe see clones, but from seed soaking the cubes in bloom fert? obviously they are way past that but why do you do it?why soak em in bloom ferts? I would thouroughly flush pots with distilled or as close to 0 ppm water ph 5.8. then let them drink just that for 2 days, they may strech a bit, but will be fine. then EC @ 1.5. imo