Kelp is a good addition to soil, compost and ACT but in moderate amounts. If used in compost tea, one can expect it to delay a little bit the bacterial division [I believe because of the plant hormones] but it does have a benefit as a food source, especially for fungi [from my experience] in the end result. If you are using kelpmeal in ACT, brew for a little longer if it is a diverse nutrient cycling tea you are looking for. If you are going for a fungal tea with very few bacteria, usually around 18 hours is good [provided you have fungi in your compost]. I use a maximum 0.25% kelpmeal and that is just with the regular livestock grade stuff. If you are using more potent kelpmeal, like the water soluble or liquid concentrate, then back off on that maximum even more.
You know, one thing about compost tea is that you really can't go wrong as long as you are not putting some evil crap in there, overloading it or unless it smells putrid. You can even make a good compost tea by stirring (vermi)compost and light foods with a stick over a period of 4 to 8 hours. It just gets better from there up as one learns to use efficient methods to boost the dissolved oxygen and extract and multiply the organisms.