Algae on plant leaves, harmful to plant?

You can use both lights; then its just high end and you'd wanna add more ferts then to avoid algae. You need to balance your tank between lights-ferts; more lights more ferts; less lights less ferts.
See I run my 55g on 30w lights here and my Vallis for example was bought late Nov last year as these little bitty few inch plants and now they're 4+ft long...personally I'd be scared to offer that tank ANY more light nor ferts right now

The full spectrum 6700K tube is far better for your setup. First, it has red and blue highlights (necessary for plants) plus green to balance for a nautral colour rendition. Second, the higher blue tube alone will encourage algae.

Using both together will provide more light which means you will need more nutrients to balance, as Angel079 pointed out. I am a real fan of the "less light is better" school headed by authorities like Tom Barr who advocate the minimal amount of light to achieve plant growth is preferable because nutrients don't then have to be as massive to balance. Without sufficient nutrients for the plants to balance the light, more light will not help the plants but algae will take over.

This fert only contains potassium and iron, according to the manufacturer's information on the website. This might be adequate if the other 15 essential minerals are present from your tap water, fish food and fish waste. Impossible for me to determine that. If other nutrients are missing, then a better fert would be a comprehensive one like Seachem's Flourish Comprehensive Supplement for the Planted Aquarium, or Kent's Freshwater Plant. These are dosed in very small amounts so a bottle will last you months with a 10g tank.

Interesting stuff, very interesting. Thank you all for the suggestions and info. will pick up some better fert sometime soon and switch to the one 6700k tube in the mean time. hehe, this is how I learn best... by "doing" first and asking questions later.

Well, at least the experience though bad explains first hand what we are saying. My recommendation for fert still lies with Seachem's Flourish Comprehensive as first choice; just make sure it is the Comprehensive, they make several products in the Flourish line and they do different things, some of which would be of no more help or even less help that the Leaf Zone.