POPETPOP Off System Aquarium - Water Filler Aquarium Mini ATO System Fish Tortoise Tank Water Level Controller No Wiring Float Valve - Blue

Good stuff to keep the water in marine tank ( need to be a small tank btw )

This product is amazing. For the price I didn't expect a lot. I was WRONG. This is a real worth bit of kit. Definitely worth buying. Easy to use and set up. Thank you

If you do not have the budget or space for an ATO and a large container, this is a great alternative to keep your salinity in check.Please mind that for larger tanks you will need more than 1 and it will look sketchy

Is e these on my small cube aquariums and they work wonders.

I'm using this on a nano marine setup. I've had a number of pump driven ATO's in the past and they have all failed over time due to various reasons. This is a simple solution which costs substantially less than any of the previous ATO's I've owned. Being a simple design, there is very little I can imagine that could go wrong with it. It works well for a nano tank setup with the limitation to how large a tank it would be suitable for being the size of the bottle that can be attached to it.

I think these are a fantastic idea, but I can’t get mine to work consistently. It will function perfectly for a couple of days, but then the entire reservoir will suddenly empty into the aquarium within a few minutes. The key to setting these up seems to be cutting the plastic tubing on a sharp angle, which I’ve done (there is a YouTube video to show you how to configure it), but I still get mixed results.The manufacturer has shipped these with a number of options to fit different widths of aquarium glass, but it is nevertheless not wide enough to fit on a Juwel aquarium with a 5mm edge. It fits fine on an aquarium with a basic glass wall (like a nano tank).