Magnesium

Hi all. I believe my plants may have a magnesium deficiency. Yellow tips on some of the leaves and a small amount of yellow dots on leaves. They dont seem too bad as they have only 3 / 5 yellow dots on one leaf. on 2 of my plants out of 4. But i have yellow tips on a good few of the newer leaves. They are almost 3 week old plants and the its only the very tip of the leaves that are yellow.
Heres a pic

So ive read in other threads/forums it may be a magnesium deficiency and that epsom salts will help.
Anyway i have just a few questions..

1: Do you believe from this pic that it may be a sign of magnesium deficiency?
2: Will epsom salts help?
3: Can too much magnesium damage the plant?
4: How much should i mix with 2 litres of water?

I dont think this is caused by nute burn as i have been giving them weak nutes (highly diluted) every second watering and i water every 3ish days. I gave them a stronger mix of nutes last night and they loved it. They perked up so much overnight but the tips didnt get any worse / better.

Cheers lads.

ps. I got a malware warning from google today coming on to this website. Last night was fine. Today was the first time i got this warning. Did something happen/False warning or website flagging?

Looks more like a nitrogen issue to me, but I could be wrong. This is a magnesium deficiency:
View attachment 3037136

Been getting the goolge alert also, no worries though. Just ignore it. I think it stems from the spam posts.

This: http://www.mjguide.com/tutorials/PlantTrouble/Merged.htm - Might help some.

Thanks man. But i dont think its a nitrogen problem. Heres what it said on the website you linked
"Plants suffering from this deficiency are distinct in their pattern of yellowing. Yellowing starts on the older leaves and progresses upward, leaving the top parts of the plant green.
Notice that the large fan leaves are yellowing and turning purple-ish. from the bottom up.

However the yellow tips are only showing up on the newer leaves. The older leaves seem fine at the moment.

Yellow leaf tips is usually the beginning of nute burn.