Picked up a pump this morning for draining the tanks. Had to skip last week when the original pump I bought failed after only one use. Serves me right for doing things on the cheap.
This new pump isn't expensive, but its hand operated. Thankfully its just one gallon per tank.
Missing a flush last week had me worried, especially with how far along the plants are. If I had to go a second week I'd have been in a bit of a panic. The chemistry of the water is probably way out of whack at this point already.