Here is what one costumer said about it.
Great product. My water has a higher KH, PH, and GH than any of the 3 test kits I bought could read and I still get 15 gallons per filter. That brings it to about $1 a gallon, but because of the simplicity it is so much more worth it to use this than to buy RO water from the store.
The water is almost entirely pure when it comes from this, it actually comes out cleaner than reverse osmosis water. DI water, at least from this unit, is some of the cleanest water you can use. It does not use salt for ion exchange, so it isn't an overpriced "water softener pillow." It removes everything - nitrates, chlorine, sediments. Water comes out with 0 hardness, 0 nitrates, 0 chlorine/ammonia, 0 calcium, 0 phosphates.
The system even includes PH adjuster and RO/DI water treatment so you don't starve your fish of what they need (water can be too clean for an aquarium).
The best part is the simplicity. It takes two seconds to hook up to your faucet, you then run a tube similer in size to an airline tube directly to your aquarium and let it fill.
Great product that has saved me a lot of money. My fish and my plants are so much more healthier than they were before I found this product