Harvesting 1 out of 2 plants sharing the same reservoir

No, your drying and growing tents require two separate environments. For drying you want to chop and hang the whole plant in a dark room that's 60°f and 60% RH. Your grow tent needs higher temps and lower humidity during bloom. Your plants will dry out way too fast if you try to dry them in your grow tent and that will lock in chlorophyll and other unwanted chemicals before the aerobic bacteria has a chance to break it down. You'll end up with harsh tasting smoke that won't burn well. Just set up a closet or something to dry your plants in.

Hey friend, how's it going? It's simple, a shoebox or a bigger box, you make holes around the box. You put something going from one side to the other, like you're hanging clothes xD And you place the buds in there, close it well, and you have the problem solved. In my previous grow, I did that and everything went well :) Congrats on the grow and hugs!

Thanks for the insight. I definitely didn't think this through before growing two strains in one reservoir. Lesson learned. Now I just need to figure out how to flush and dry my first harvest.

I would NOT dry in your grow tent. You do not want photosynthesis occurring after harvest. I have a separate tent just for drying which makes it easy to harvest one plant sooner than the others. I would not flush in a system like yours. Switching to just water won't hurt but it certainly will not help the plant that is still trying to fatten it's flowers. It's one reason why growing different varieties is not the best in a shared hydro system. If growing in soil it's much easier as you can give each plant what it needs. In your case is there any way you can rig a temporary water only system for the plant you intend to harvest?