Can dehydration cause dizziness when i stand up it's hard to describe bit 1 or 2 seconds after i get up i go light headed and see a blue colour and start to fall over this lasts about 1 to 2 seconds and them i'm fine also this doesnt happen everytime?

You may well have a postural drop in your blood pressure upon standing, which results in pre-syncopal symptoms. Although dehydration could be a cause, other problems such as anemia, dysautonomia, medication/ drug reactions are some additional considerations. Have your doctor perform a full examination.

To avoid dizziness from dehydration, drink enough water daily so that your urine is mostly colorless. If that does not relieve the symptoms, it would be prudent to see a doctor. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV vaccine.

If the hydration technique suggested by Dr. Singh is not the complete answer, see your GP for an examination. I the meantime look into Orthostatic Hypotension.