Toilets not working

[Ruth Edwards]

My hams have been using their toilets happily up till now but both seem to be "out of order".
They both seem to like peeing in an enclosed toilet rather than an open dish and they've been using Potty Litter for a while happily.
But the potty litter doesn't seem to absorb the smell of Daisy's wee any more. Her toilet was horrible on Wednesday so I cleaned it out and put in fresh potty litter and then she immediately weed in it once and the smell was terrible even though the little balls soaked up all the liquid. I've tried guinea pig litter too, same thing.
Little Cotton seems to have gone off using his and now wees on the corner of his wheel stand and he's put fitch in his toilet. Also his toilet seems just a bit small.
Do any of you think there's a better substrate for toilets I could try, and do you think a slightly bigger enclosed toilet would help?