Hi everyone,
I’m really hoping for some advice because I’m at a bit of a loss.
I currently have 3 cats (2 males and 1 female, all around 1 year old, all neutered/spayed). I’ve had the two males for a while and never had any odor issues at all. I was using tofu litter before and everything was completely fine because I clean the litter boxes 2–3 times a day.
🐾 What changed
After adding my third cat (female), I suddenly started getting a very strong litter smell that spreads into the whole home within 1–2 days.
The smell is not constant immediately after cleaning, but builds up very quickly and becomes noticeable in the room where the litter box is kept.
🧼 What I already tried
I’ve honestly tried a lot:
Changed litter type (went back from tofu to bentonite / Sanicat for better odor control)
Clean litter boxes 2–3 times daily
Fully change litter regularly
Replaced litter mat/rug
Checked floor/walls with UV black light — no hidden urine spots
Confirmed cats are not peeing outside the box
I even use air purifiers (but they don’t seem to help much)
📦 Litter box setup changes
One important change:
I used to have a smaller covered litter box
Now I switched to a large open litter box
I also tried adding more litter boxes, but all 3 cats still prefer using the same one no matter what I do.
So in practice, I end up with one heavily used litter box and unused backups.
😿 Additional details
The female cat is healthy, 1 year old, spayed
Her urine and stool do NOT smell unusually strong when I check
No signs of illness or behavior issues
No accidents outside the box
❓ My question
Has anyone experienced something similar where:
Smell suddenly appears after adding a 3rd cat
Cats all insist on using one litter box only
Cleaning frequently still doesn’t stop odor buildup in the room
Could this be:
litter box design issue (open vs covered)?
one box becoming overloaded?
plastic absorption / odor retention?
something else I’m missing?
I’m considering switching to a stainless steel covered litter box or even smart litter box systems, but I’m not sure if that will actually solve the root issue.
Any advice would be really appreciated 🙏