Rookie questions.

Also the edges of your leaves are turning up thats heat stress.

Thats either a lockout or manganese def I had the latter on a grow recently. Try the ph 6 flush and ph test the run off. If thats to high / low adjust as required. If its ok dilute some bone meal in warm water let it cool and feed it to add manganese 👌

I would start by flushing w/ 6.0 ph and feed with half dose.

Hi Gflmae, So at first I thought it was just a simple condensation burn...then I see what you mean. Look on the first photo it seems like the new leaves are less affected, I would say go easy on that nute this plant is a bit sensitive or you have been heavy handed on the nute. I suspect it will come back just fine in a week or two and you can remove all "the yellowing leaves of disappointment". I think you have done a real good job so far, nutes can be tricky...less is often more. With budget nutes they will often recommend that you use more than you need just so they sell more product. It happens. Im strictly organic, you can pop over to check my diaries anytime if it helps. Am here if you need to ask any questions. I won't have all the answers but after growing organically for 30+ years I have a lot to offer. Just PM me. I really hope that helps. As ever Sticky Buds!

If your runoff is that high you really need to clear the buildup of salts in the medium because it is messing with your pH. Make sure your letting your water sit for 24 hours to get rid of the chlorine or that will mess with your pH.

I fed it with PHperfect(GMB) On 5L I added 8ml each nute. when I mixed everything ph was @6.5 but when I tested the runoff it was 7.2 and 7.4 Should I flush it?

You need to start a diary here, mate.. it would give us a lot more information that would be useful to us in trying to help you... What I see from the pics is a calcium deficiency - but the question is going to be WHY... normally, nutes will contain enough calcium however sometimes you need to add more with some calmag... other times, the pH is not in a good range (6.2-6.5) so the plant can't absorb the calcium that it has available... and still other times, too much nitrogen in your feed can create a lockout again preventing the plant from taking up that nutrient... But which it is for YOUR grow, I can't say... just need far more information so please start a diary! Good luck!

How much do you Feed ? Some Leafs Seen to have Not enough nitrogen