What do you mean by light mix soil? If you mean a soil-less product then it will likely contain a lime amendment to buffer PH, in this case its hard to screw up if u keep the ph of feed between 5.5 and 7 it will liekly stay where it needs to be. If this is a purely inert soil mix that has no buffers or anyhting then you will have to keep the PH more in line at around 5.8. IMO if you were to do this i would just go with 100% soiless product because if u mix it with clay it will likely make a solid brick that has less aearation ability, or go pure hydro and ditch the soil all togeather.
It's just a light mix soil such as this, lasts for about a week or two.
It seems like the soil you linked is very similar to what i use for soiless hydroponics.; Casnt tell if it has lime in it but the label will say. IMO you will have better luck just using 100% this soil, or this soil mixed with like 30% perlite. Clay will hold no air, and when mxed with soil will form a medium that holds less air and less water than the soil and perlite.
Unless you have already purchased that soil, which im sure will work fine, i would buy some Sunshine Mix #4. It is very similar top your "light" soil but it has myco's (micro organisms) and lime and makes a perfect little sponge in a pot that holds air and water. This stuff has almost no nutrients so you will also need a complete nutrient line like GH Flora series. If you have already bought your soil i would suggest mixing the two. I buy the sunshine in the compacted bail and it lasts me like a year for $30-$40. And the GH line is like $30 and lasts a long time as well.
The feed is synthetic, basically hydro feed with calN. The soil is well, the only available option bar coco/full organics.