Maxicrap I mean crop liquid has chlorine in it. It is not very concentrated (1oz./gal!) and cheap. Well you get what you pay for I guess. Their powder doesn't have the Cl I think. My garden gets a higher quality kelp. It costs me more $ but worth it IMO. I like Techniflora Soluble Seaweed 1-1-16 (danks Matt). Super concentrated at 1/8 tsp/4L! As for liquid kelp I like Thrive Alive Green (1-2ml/L and OMRI) and Extreme Serene (15ml/gal but I use more like 5ml/gal), they reach up to the lamp great with foliar application with either of these high quality kelps. Earth Juice offers meta-K which is 0-0-10 I think. What are you looking for in specific? K boost is what I assumed.