I used to use the same siphon in all nine of my tanks, until one Betta got columnaris and spread it to two others. It was right before Christmas, 2019, and I spent Christmas Day in tears. I managed to save one of the fish, who is still alive now but has permanent scarring to his fins.
Since then, each tank has its own siphon.
For nets and metal tools, I rinse them in chlorinated water (tap water) and make sure they are fully dry between tanks. If I don’t have time to let them dry, I will swish them in water with bleach added then in water with extra dechlorinator added.
I have one set of tools and some nets I use across all my tanks. When not in use I store them in Jungle Net Soak. Haven’t had any cross contamination issues.
I have two main tanks and a quarantine. Each tank has its own siphon. I do share aquascaping tools and vials for API testing, but I spray them down with a 1:1 vinegar wash in between tanks. I have a dedicated CLEAN (only dechlorinated clean water) and DIRTY (waste from the tank) bucket but only one set. I spray down the DIRTY bucket with 1:1 vinegar if I know there’s something going on (but nothing that goes in the tank touches the inside of the bucket so that feels excessive). I have a dedicated net for the quarantine tank but use the other one so rarely I just spray it down with 1:1 in between.
Secret-Agent-Brunch 
I use the same for all my tanks, sw and fw
I used to use the same siphon in all nine of my tanks, until one Betta got columnaris and spread it to two others. It was right before Christmas, 2019, and I spent Christmas Day in tears. I managed to save one of the fish, who is still alive now but has permanent scarring to his fins.
Since then, each tank has its own siphon.
For nets and metal tools, I rinse them in chlorinated water (tap water) and make sure they are fully dry between tanks. If I don’t have time to let them dry, I will swish them in water with bleach added then in water with extra dechlorinator added.
I.e. net, scissors, tweezers, baster, etc.
I feel like you don’t have too but you always run the risk of spreading things, algae, bacteria, diseases etc
Depends on if I have something i suspect bad in a tank. I’ll isolate my tools until I figure it out
I have one set of tools and some nets I use across all my tanks. When not in use I store them in Jungle Net Soak. Haven’t had any cross contamination issues.
I have two main tanks and a quarantine. Each tank has its own siphon. I do share aquascaping tools and vials for API testing, but I spray them down with a 1:1 vinegar wash in between tanks. I have a dedicated CLEAN (only dechlorinated clean water) and DIRTY (waste from the tank) bucket but only one set. I spray down the DIRTY bucket with 1:1 vinegar if I know there’s something going on (but nothing that goes in the tank touches the inside of the bucket so that feels excessive). I have a dedicated net for the quarantine tank but use the other one so rarely I just spray it down with 1:1 in between.
Yes, I do in order to prevent cross contamination.
I use the same tools for all my tanks, same siphon, scissors, net, etc., it makes it easier to keep everything in one place.
no but since ive had hydra in one tank i do wipe them down with white vinegar
looks like pic has hair algae. i keep getting that no matter what i do :/
I try to and then inevitably jumble them all up.