Crystal Litter Recommendations

The ScoopFree system is designed to work with crystal litter only.  Clay litter and other forms of clumping litter can damage your machine.  There are several crystal litter options on the market, some better than others in terms of absorbency.

The actual size of the crystals is critical as it should not be too large (see below).

Specific Litter Recommendations

After a great deal of research and experimentation with various litters and lots of feedback from other cat owners we have found several good options for crystals, depending on your personal shopping preferences. The actual size of the crystals is critical for proper operation of the machine. The larger the crystal size, the more it is able to absorb moisture and hold odor, up to a point. Crystals that are too large are generally lower quality and will not absorb as well, and also tend to cause problems as they’ll get pushed to one end of the tray and pile up. The smaller size crystals are also cheaper, andtend to “track” less, but we’ve found they also aren’t able to absorb as much and quickly turn to slush.

During this whole development process we did a lot of experimenting to find a crystal size that would work best. It became quite frustrating, between widely varying levels of quality, going to the store and finding an empty shelf, the hassles of lugging large heavy bags home, not to mention trying to figure out the ideal amount to try to measure out each time (see below). We finally ended up working with a crystal manufacturer to develop our own line of premium crystals called “Just the Crystals” (, which are also available with free shipping to your door from Amazon.  These are conveniently packaged at the ideal 4.4lbs per bag, which makes life a lot more convenient. We opted for fragrance free, as we feel a premium crystal should remove odor rather than add the perfumed smell of a cat litter brand to your home. 

If you prefer buying from your local store, there are a few other options out there.  Here are a few with my own personal notes:

  • Fresh Step Crystals — excellent (premium) crystals of the correct size with good absorbency, however with fragrance. Expensive from some stores and not always available, plus only available in 4lb and 8lb bags so will require some measuing.
  • Dr. Elsey’s crystals and Mimi Crystals (from Walmart) – good options depending on availability. Mimi Crystals are usually extremely cheap, however are a very small grain and so tend to not absorb as well and therefore don’t last as long as a premium crystal, turning to slush.

Regarding Fresh Step, we have found that often you can actually get a better price at Target, Walmart or similar large retailer rather than your local pet store where the prices tend to be a bit higher.

For our friends in the UK :  As some of the above brand recommendations are not all available in the UK, we recommend contacting Crystal Clear Pet who are extremely knowledgeable, as we have been working with them for years and they have helped a lot of our Forever Litter Tray customers.

For our friends in Canada: We’ve had reports that Dr. Elsey’s Long Haired Cat Litter works well. Available at Petsmart for about CN$13 per 8lb jug. 

How Much Litter Do I Put In The Tray?

4.4 lbs. of good quality crystal per change works the best and will last the longest and help control odors longer. Using only 4lbs (which is the standard bag size of many litters) won’t last nearly as long. Definitely don’t use more than 4 1/2 as it will overload the machine. The flipping of the rake on the return trip is controlled by drag (or weight) of the amount of litter in the machine. Too little, and the rake won’t flip, not to mention less absorbency. What’s interesting is I’ve found that you can go notably longer between changes (litter lasts longer) just be ensuring you have that extra half pound or so in there (with about 4.4lbs being ideal).

A good way to find out if a crystal litter is a good choice is to read the Amazon reviews. There are some brand names out there that don’t absorb well, and some that are too large. There will be comments in the reviews that will help you make a good selection.

Warning: The following crystal litters have been found to definitely be too large and will NOT work properly:

Petco Pet Gold crystals
Pestell Clear Choice

Extending The Life Of Your Crystals

Below is some info sent in by Chuck, who has been using our product for several years now. This is good info, which also substantiates what many others have said about doing an occasional “rake and stir” (which is covered in more detail in our Basic Box Maintenance video on the How to Use page).

“The most important tip on making the litter last longer is good air circulation. Silica gel absorbs liquid fairly quickly, and releases it as water vapor fairly slowly.

When used as litter, it absorbs urine and dessicates solid waste. Unless the silica gel itself can dry out (by releasing water vapor), it won’t last long at all in a litter box. So, it works better in the summer than in the winter, and better on dry days than rainy ones.

If you can place the litter box where there’s a breeze, the litter will last a lot longer. Or, you can try what I’ve recently done: put a small fan above the box, so that it constantly blows air down onto the litter.

During the Winter and Spring, the litter has been lasting only 10 days with two cats (in the Summer, it was stretching out to 14 days). With the fan, in the Spring, the litter was still OK after 15 days.

The litter still needs to be stirred every few days, especially towards the end of its useful life.”

Crystal Litter Product Safety

Safe Handling by pregnant women:

Unused (clean) cat litter is safe for handling by pregnant women. However, pregnant women should avoid handling used cat litter. Toxoplasmosis, an illness characterized by cold or flu-like symptoms, can be transmitted by cat feces. It is especially serious in pregnant women because it can cause birth defects. Immunosuppressed persons may also be susceptible to toxoplasmosis. For further information, consult your doctor.

Safe for cats:

Commercially available crystal cat litters have been extensively tested and are safe for your cat. Its basic chemical makeup can be closely compared to sand. The industrial name for it is silica gel, which is non-crystalline, porous and a safe substance most commonly used to absorb excess moisture in flowers and food or to protect materials such as leather or computer equipment from humidity.