Yellow /white tips

The grow has been going great. Now 4 and a half weeks into flowering and I noticed some yellow spots on a couple of leaves but pretty much the very tips on all the leaves are yellow/white.
They are in growing in FF Ocean Forest soil, 5 gal pots. Nutes include FF trio at half the FF recommended dosage. I have not given them any FF Grow Big in two weeks though... Watered ever other day with distilled water. Also supplement GH Cal/mag and occasionally I have added some Molasses.. Sitting under a 400w HPS which is about 12 inches above.
Overall, the girls look good, would just like to figure out what is causing these issues now and correct them before they get worse.. Researched nutes deficiencies etc but my results were inconclusive so time to ask the professionals..
Any ideas? Thanks..

Basically means you’re right on the edge of your feeding limit.

Also, from the first pic I can see what looks like the beginning of intervienal chlorosis. Which is usually a deficiency in magnesium..

Nutty sKunK said:

Basically means you’re right on the edge of your feeding limit.

Also, from the first pic I can see what looks like the beginning of intervienal chlorosis. Which is usually a deficiency in magnesium..

Click to expand...

Thanks for the reply... Yes, I do use minimal nutes. Reason being this is my third grow using FF soil and the trio and have found that combo to be pretty potent. Out of the three, this has been my healthiest grow.... So far....
I do supplement GH Calimagic but only give it the amount on the label (1 tsp/gallon)
Do you suggest I double that up (or more)?

I wouldn’t up the cal Mag. There’s no sign of calcium issues. What could be happening Is a couple of things.

First off is that your plant simply wants more magnesium.

Or the ratio of calmag your giving is slightly wrong. In that the calcium could be building up and starting to block magnesium.

I would say judging from the pics it’s the first scenario as there’s no other issues. Since too much calcium blocks a number of nutrients. Probably a dose of Epsom salts would do you good.

Amounts vary. Some say 1tsp per gal, some say 2tsp. Some say 1tbsp amd others say 2tbsp.

I used 2tbsp and they loved it. But I would recommended using less as you don’t want to over do it. 1-2tsp per gal is enough I’d say

Freshly distilled water and nutrients tend to bring your water PH down into the 4.5-5 (distilled water is ~5..

If your soil doesnt buffer well you could be seeing PH swing issues. Usually that shows with rusty spotting on the leaves followed by calmag lockouts and then macros start locking out shortly after...

I am not very experienced so take that with a grain of salt... the PH numbers i have witnessed first hand though...