yellow tinting on leaves?

[KHAN]

Since I've put the NFT system on the plants have shown some good growth, I'm slightly worried that the leaves seem to be developing a yellowish tint, at the tips and edges. I've heard this could be a few different things, I dont think it's overwatering (since its in the nft system i hope not)

Each of my tanks are 9 gallons, I have a CF reading of 6, a ph of 5.5 and have placed a little oxygen in the tank a few days ago.

Here are some updated pics, any advice will be gratefully received ;)

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[LIP]

It might be too wet, or it might be ferts...

Im no good with hydro

[MrGuy]

Yellowish leaf ends generally mean to much nitrogen. HOWEVER, I am only familiar w/ soilless growing. I know some of the babes I used to grow would start out w/ yellow leaf ends and gradually go greener.
Water temp also turned out to be a problem that was difficult to solve.
Keep Posting! I wanna see how yer girls turn out! :)

[britewire]

Use a minimum amount of nutrient in this early stage. I prefer only root stimulator in this stage

[amstron]

Yellowish leaf ends generally mean to much nitrogen.:)
thats strange, I always found that yellowin leaves was too little nitrogen.

[KHAN]

Yeah I had heard the same thing..... Guess I'll just leave them and see how they go.

[MasterBaker]

yellow spots have been showing up recently on two of my plants too (ima first time grower, indoor, soil)
i have read that it was because of too little nitrogen as well and just gave them some nutrients (12-6-6 to start em out, i heard when you start feeding 20-20-20 is ideal, but i wanted to start out smaller since they are only two weeks old and 7 inches tall)
ill let you know if the yellow spots go away in a few days (hopefully)

happy growing

[KHAN]

thanks dude, what's your cf reading?

I've got them at 8 but dont know whether to push them up, some of the tips are a little yellow but most of them are a great green plush color. I think maybe I fert'd too early but they catching upto needing it now.