Is it ok to give all my cats Ph control food?

[NightWanderer]

I have three cats but one has been diagnosed with crystals in his urine. The vet says he needs Ph control food. It's hard to separate them for feeding so is it ok just to give all three of them the Ph control food?

Can't you feed the poorly cat in another room? It'll be an unnecessary expense if they all have the same,i looked into it and nearly fainted at the price!

It is really expensive. I have tried feeding one in a separate room, but one of the 'healthy' cats is very shy and won't come out if the kids are around, so it's easier to leave a bowl of dry food for him to access when he feels the coast is clear. I will keep trying different things and see if I can find a solution. Thanks!

You can get cat bowls which only open for a particular cat - they work by reading their microchip or an RFID tag on their collar. They are expensive but might work out cheaper than feeding all three Ph food in the long run?

here but possibly cheaper from Amazon/Zooplus or something.