It was Ray's fifth donation after he was encouraged to do so by a friend, Jamie, who encouraged others in his running.
"It was something I always wanted to do because my mother did it, but I never got around to it, so when he [Jamie] had that sheet I put my name down," Ray Knox said.
The Dunedin family are speaking out during the New Zealand Blood Service's annual donor drive - dubbed Know Your Type - to encourage others to give blood.
Erin was inspired by her father giving blood initially but had to wait a year to do so as she was too young.
New donors can start donating blood from their 16th birthday and weight 50kg or over. If you are a first time donor under 25, you must also meet the height and weight criteria.
"I thought it was great and I wanted to do it too but I was too young at that point," Erin said.
Her mother donated for the first time when her daughter did.
"Erin and I don't have a blood type that people need a lot of, so we've got B+ blood and only a small percentage of the population has the blood," Margaret Knox said.
Ray Knox has the most common blood type in New Zealand, O+, and said you never know who might need your blood.
"Someday someone you know might need it and there's always people needing it, so if you can do it why not?"
Each year the service needs to recruit 20,000 new donors in order to replace those who exit the list due to a variety of reasons; including illness, travel to some countries where the presence of tropical diseases leads to a mandatory stand-down, retirement or personal choice.
About 50 per cent of New Zealanders don't know what their blood type was.
The decision can be a life-saving one - with blood donations saving and improving the lives of around 27,000 people a year in New Zealand - and the process only takes five minutes in total.
"We never take the commitment of our amazing donors for granted," New Zealand Blood Service's marketing manager Asuka Burge said.
"Taking five minutes out of your day to find out your blood type and sign up to become a blood donor could mean the difference between life and death for someone. Every whole blood donation has the potential to save three lives.
"We think that's three great reasons to become a blood donor."
>> NZME is the official media partner of the New Zealand Blood Service's 2017 campaign
KNOW YOUR TYPE - AND SAVE A LIFE
The New Zealand Blood Service is running a series of 'Know Your Type' events this week allowing Kiwis to find out what type of blood they have, and become a donor.
Every year the NZBS needs 20,000 new donors to step-up and find out if they are the type to save a life.
All you have to do is come down to an event, find out if you meet the donor eligibility criteria and one of the Blood Service's staff will test your blood through a quick finger prick. Within a couple of minutes, you'll know your type and you can register to donate.
Preference for blood typing will be given to those who meet the donor eligibility criteria which can be found on www.nzblood.co.nz
Remaining events include:
Tauranga - Bayfair Shopping Centre, outside Kmart, on Saturday
Christchurch - The Blood Donor Centre, 15 Lester Lane, until Friday, and the Cashel Street Mall on Friday
Dunedin - Meridian Mall on Thursday
>> For full times and more information, visit: https://nzblood.cwp.govt.nz/missingtype/blood-typing-events?stage=Live
RED GOLD - THE GIFT OF LIFE
•New Zealand donors gave blood a total 164,000 times between July 2016-June 2017
•Last year donors saved and improved the lives of 27,000 New Zealanders - about 74 people a day
•Each year about 20,000 people leave the donor registry for a number of reasons; including age, ill health, pregnancy, overseas travel and personal choice
•Those defections have to be replaced to keep up with demand
•85 per cent of our population are A and O blood groups, the types most in demand
•More than 50 per cent of Kiwis don't know what their blood type is
•Just 4 per cent of the eligible population are donors; 109,202 New Zealanders
•111,146 whole blood units were collected in 2016-17
•One whole blood donation has the potential to save three lives
•You can donate whole blood every three months
•Whole blood donations (red cell component) only last 35 days
•Platelets must be transfused within seven days of collection
•Plasma can be frozen for up to two years and blood products made from plasma can be stored for up to two years
>> Source: The New Zealand Blood Service