What to fill Skylan stands with for Harbeth SHL5s

Skylan stands for SHL5s: could someone please tell me what to fill them with?
Skylan advised PURINA MAXX kitty litter, but I cannot find this in the U.S.
Should I use play sand, sand kitty litter, clay kitty litter, something else?
Thank you.
Try using 6 DH Labs Ceramic Cones (small ones, points up) from Golden Sound and listen to the magic.

They will not harm the speakers finish, because points are slightly rounded and are finished in gloss black.

A synergistic match with Skylan Stands.
Use kiln-dried sand. This is all you need, and it's cheap. Buy it at your local home hardware.

Don't bother with lead-shot, cones, or any type of 'filler'...it does not and will not affect sound quality.
I have been using lead shot for years but only just now realized how bad it is. In steel stands [sound anchors, VPI TNT stand ] it added an enormous amount of midrange energy that did not belong there. I recently put my Spendor S 100s on the dedicated steel stands filled with lead shot. I had never liked the sound of these but didn't know why. Very bright. I then placed the speakers on a Mapleshade Quadrapier stand [ discontinued maple stand] with upward pointing cones [Mapleshade and Star Sound] and the sound changed drastically for the better. I recently got a VPI TNT stand and , following their recommendation, immediately put in 40 or 50 lb. of lead. I have a 24"x 18" x 3" Michigan Maple Block on top of it , resting on large cones. Had trouble getting my Scoutmaster to sound right. Tonight I moved it onto a dedicated turntable shelf I just got for my Star Sound rack. Same effect, much quieter, more natural. It uses steel bearings for dampening. Disclaimer, I have recently resumed being a small audio dealer. The above experiences represent my efforts to make the products I am going to sell sound better. I have a pair of Skylan stands for the Spendors on order and am eager to see what they do.