[cameraman]

Mine came with four 300s and one 200. Two of the 300s I only use in the sealer, and the other two I move back and forth between the de-ox and the dye (and tstat moves with them). I use two at a time just for faster heating. Rinse thoroughly with RO (reverse osmosis) water between moves. You might want to pull the heater up out of the solution to let it cool a bit before hitting it with cold water. I haven't had one shatter but I suppose it's a possibility. Don't forget to unplug it before pulling it - I melted a tub pretty good once.

I leave the filter cage on but the foam filter out.