Help lowryder #2 dying! Nute burn/Phosphorous Deficiency

Recently I had to flush my lowryder 2# because the pH was off and it was experiencing some deficiencies. After this it was growing perfectly and looked completely healthy again. I checked my plants this morning and overnight there were loads of brown patches coming in from the sides of the leaves which looks like nute burn and is quite probable because I added some nutes [but not alot] after I finished flushing. There are also tiny little yellow spots in places, and the leaf veins look pretty yellow. I thought it could of been heat stress because it's pretty hot in my grow box and the newest/closest to light tips had been affected pretty bad. The leaves that have been damaged seem to be pretty random, apart from the new growth as only 1 leaf in a set of leaves is sometimes damaged with the others looking healthy.

Two or three leaves in random places also have sort of twisted/curled inwards onto itself, with something that looks like sticky/moist patches on them. This is most prominent at the lower leaves which have started to begin to wilt, although alot of them look healthy. This looked alot like phosphorous deficiency but I have nute burn anyway so I have no idea.

My pH is about 6.5 as I flushed it to this last friday.

I think mold if your humidity ia too high

A potting mix with 4 weeks nutes for seedlings. It's 25 days old now so it was almost over

lol you had a nutrient deficiency so you flushed, then gave them more nutes less then a week later. Settle down tiger, I'm guessing your new to this. Flushing is a last resort and will likely cause more problems then it will solve. A deficiency is a hell of a lot better then over nuting or over watering. Give them nothing but water with less than 150 ppm for the next week and a half. Then evaluate your deficiencies. It's likely that flushing to solve your pH problems then adding nutes it going to bite you in the ass hard. Your plants are going to give you some very mixed signals, and your going to have to resist your desire to respond. Regular pH balanced water, thats it! No foliar, no nutes, just water!

How close is your light to the plants btw those are some dense nodes!

The pH was way too high so it had lockout, and i thought the flush would get rid of the soils premixed nutes so that's why I added them. Yeah it's my first grow. How do I measure ppm? Is bottled water around 150?

Also what should I do with the damaged leaves? Will they repair or should I cut them off?

Depends on the bottled water, you want distilled water not drinking water. You need a TDS meter to check ppm (20 bucks on amazon). Do you test ph with strips or a ph meter?

Distilled water will be less than 20 ppm and should be around ph 7.0 which isn't ideal but it will do.
How did the ph get thrown off in the first place?

If your going to use distilled water and have a ph meter let me know. There's a major problem using these things in combination that your probably going to need a buffer on before handling.

PH the soil...thats the final say in if a plant is picking up nutrients it needs...

Also the leaves will likely not recover, I would leave them though. The plant will prune them off itself, and from my experience pruning off leaves during a problem like this only mobilizes the problem.

looks like ph ..flushing really has no or very little negative affects on the plant as long as you let the soil dry out completely after and never flush back to back..................... also when your trying to remedy something with your plant try one thing at a time and give the plant 2-4 days to react......i know its nerve racking and you just wanna fix it NOW but thatll cause more harm than good

I messed up the pH by using regular untreated tap water, (stupid I know). I'm using test strips now.

The light was about an inch or two away, it's further now. Im using a 125w 2700k cfl.

So the general consensus is to just use ph'd below 150 ppm water? This is a low budget grow so I don't want to buy a ppm meter would bottled water with the correct ppm be okay? Or filtered water from tap?

I'm also using lemon juice to lower ph I know it's not the best but will it manage to see my grow through?