- Joined
- Jan 18, 2026
- Messages
- 3
- Reaction score
- 13
- Location
- Melbourne
- What state or country do you live in
- Australia
Hi everyone,
I’ve recently bought my first saltwater tank, it’s a secondhand Waterbox cube 20.
I’m running the tank with some citric acid at the moment to give it a good clean. I was cleaning the corners with a toothbrush and I’ve noticed what it looks like blade marks from the previous owner.
Should I be concerned about them? Should I reseal the tank or add some extra silicone on the corner?
Thanks for your help

I’ve recently bought my first saltwater tank, it’s a secondhand Waterbox cube 20.
I’m running the tank with some citric acid at the moment to give it a good clean. I was cleaning the corners with a toothbrush and I’ve noticed what it looks like blade marks from the previous owner.
Should I be concerned about them? Should I reseal the tank or add some extra silicone on the corner?
Thanks for your help

