Lol, well, hot tubs or juzcuzzis and the like all use the stuff too! After you had issues with bacteria on your cuttings stems , did you run a high concentration of bleach and water through it for a couple hrs? Once the bacteria has gotten in a cloner, it's really hard to get it out because it lives in every nook and cranny and will come back round after round, even if the Temps are cool (it usually happens from too hot of Temps, but after its established it lives in any Temps really). You'll need to disinfect it, even the foam inserts (I'd suggest buying new ones or boiling them for an hr or so). Good luck man
Ps. Stem rot from cloners is on part with broad mites and root aphids fwiw, really bleach that thing with lots of bleach