A Realistic Alternative To Water Changes?

It is just carbon, made in a physical shape to trap tiny particles. The usual way of removing fine particles is with filter wool.
Being carbon it will also remove organics from the water. These include things which cause yellow colouration and odours - we already have carbon granules and carbon sponges that go in the filter to do this. 


They are marketing this as a way to get rid of cloudy water without doing water changes. But the members of this forum know that we don't do water changes just to get rid of cloudy water; we don't have cloudy water but do water changes anyway. If our tanks looked like the one in the link, we'd be panicking because we let it get like that!



Personally I think it is another gimmick, a bit like Tetra Nitrate Minus, aimed at people who think fish tanks are a living ornament and are not prepared to care for their pets properly.

It is a popular misconception that you buy a tank, fill it with water, put fish in and just feed them. There is the misconception that a fish tank does not need any looking after; that fish are maintenance free pets. That's how tanks end up like the one in the ad. So many people will turn to any gimmick to avoid work.

Hamster cages have to be cleaned; horses have to be mucked out. Why should fish be different?
Our temporary cat has a litter tray, which he doesn't like but has to use when he can't get outside. Our son doesn't just leave everything in there, he empties it. Not doing a water change is like leaving the litter tray untouched for months, which is how tanks get into the state of the one in the ad. The cube is the equivalent of using an air freshener to hide the smell from the unemptied litter tray.


That's why forums like this exist - when things start to go wrong, the owners turn to the internet for help. We can educate people in how to actually look after their fish 

Wholeheartedly agree with Sue. It's aimed at those who think their "water is fine if it's crystal clear", when in reality water could look ok but have ammonia and nitrite or high nitrates if not being maintained as it ought to be.

It's advocating washing with water and soap , without even a mention of very heavy rinsing required to get rid of any traces of soap!

I don't understand how washing it will refresh the carbon - I thought it (I know my chemistry is poor at best so won't attempt to get wording right) got full and couldn't absorb more, washing it won't change this surely?

@Matt  this obviously uses a form of chemistry that we were unaware of. 

Or perhaps it's magic carbon, or magic soap.

Washing with soap is when it's new; after that it is just rinsed. It does say (with my italics)

    Wash the cube with warm water and soap before using.
    Recommended placement is near the water inlet of the fish tank pump.
    Do not position the grid filter downward, otherwise, it will clog up and affect the filtration effect.
    For best results, rinse or replace the filter every 3 to 6 months.

All rinsing will do is remove the usual brown goo that builds up in filters.

The information on this cube also sounds a bit like the marketing that came with the launch of the Hydra filters.
https://www.practicalfishkeeping.co.uk/features/review-ocean-free-hydra-30-internal-filter/

Things adsorb onto carbon; that is, they stick to its surface. But with something like a carbon sponge, things will also get absorbed - penetrate inside the sponge part