1st Grow Critical 2.0 Auto Dinafem - Need Help Please

[Irish Automan]

Hey everyone I'm New to growing and have just ran into a problem with one of my plants. There is yellowish burn or something on the tips of my leafs I dunno what it is and its starting to annoy me..
They are 17 days old now on the end of the first week I gave them half of the recommended dose of what is on the bio Buzz schedule chart I gave them some bio root juice and bio grow I never ph the water when I fed them untill yesterday I actually forgot to do that. Maybe that Is the problem but I'm not sure I'm hoping you guys can help. Here is my set up of what I'm using. Before I start I have only waterd them three times since I put them In to there pots. 1st time just plain tap water one week later I gave them root juice and bio grow and last night I gave them water ph 6.5

18ltr pots
plagron grow mix soil
600watt hps light
bio root juice and bio grow
Using a 1.2x1.2x2 grow tent

If I have anything left out plz just ask. Here are some pictures of the plants and u will see what I am talking about. Thanks in regards to any help u give or information

 

[Irish Automan]

 

[Irish Automan]

Sorry about double post still trying to get used to this site

 

[lazarus]

Looks like nut burn to me. I always start at 1/4 strength and then work my way slowly up to 1/2 strength. I rarely end up using full strength (as per manufacturers advice) as that tend to burn my plants. Keep in mind manufacturers has a economic interest in you useing a lot of nutes. Soil often contain nutes enough for the first 2-4 weeks, but should say on the soil pack.

 

[Irish Automan]

Looks like nut burn to me. I always start at 1/4 strength and then work my way slowly up to 1/2 strength. I rarely end up using full strength (as per manufacturers advice) as that tend to burn my plants. Keep in mind manufacturers has a economic interest in you useing a lot of nutes. Soil often contain nutes enough for the first 2-4 weeks, but should say on the soil pack.

Thanks for the reply I gave it a flush last night and just waiting to see will it come around looks better today and has not gotten worse since last night. The man in the shop said the soil will have nutes in it for about 6 weeks but me been me I just wanted to give it the extra boost as its my 1st grow its trial and error but one of my plants has really busted out and growing massively compared to the sick one. I just don't understand why one is growing perfect and the other is not as I gave them the exact amount the same. Would It be a good idea to add new holes to the end of the pot for better drainage as to me last night it took ages for the water to pass threw the pot when I was flushing?? Once again thanks for the advice