Can I use this tomato feed?

I just put my plants on 12/12 lighting after 6 weeks veg. Up until now I've been feeding a a basic liquid seaweed, progressively feeding it more up to it having a full dose. They are doing well. However I ran out of it yesterday and all I could buy was some npk tomato feed with seaweed extract. Can I just switch to using that at full dose as my basic feed or is it completely different to liquid seaweed? ? Before it ran out I was hoping to feed it the seaweed for another week or so before using some proper flowering nutes. But I don't want to shock my plants... Thanks

Start with 1/4 the recommended dose on the bag, and don't overfeed. Overfeeding is much harder to correct than underfeeding.

What's the npk of the tomato feed, what was the npk of your old feed?

Buy yourself a good EC meter and answer your questions easily. If you don’t have one do as @Rurumo suggests. Start low.