Are Kent DI cartridges standard size?

[John Steidl]

I need to replace the cartridges in my Aquatic Reef Triton. Since it looks like ARS is out of business, I thought I might try the Kent; I want to try one normal cartridge and one Hi-S for silicate in my water. The Triton uses what I think are standard cartridges; they're about 9.75" x 3". Can someone confirm the Kent's are the same.

Or do you have another brand you recommend?

Thanks.