I don't think that a 29uF is proper for a 70watt HPS. It requires a 7mfd (equates to uF)
This link has what you want for about $8usd
http://www.atlaslightingsupply.com/cap_ignitor.html
This link has what you want for about $8usd
http://www.atlaslightingsupply.com/cap_ignitor.html