Plant Fertilizer Carbon Source Easycarbo & Profito 500ml 2 Pack

Can Anyone tell me if these products are safe in a Tank containing Apple snails?

My plants are all bound up to rock & wood, not rooted in gravel, will this product help them?

Will the Easycarbo be less effective if I shake the bottle before use (cap still on)? I have a habit of doing this with most bottles

Hi how meny doses would it need for 19 l tank ?1 per week or 0,5 ?thanks