Loose stool issues again :(

Hi,

So I adopted a 4-month-old little boy about 3 or 4 weeks ago. I also have a 8ish month old girl I rescued in August.

When I first brought home Severus Snape, I had to put him right on the food I was feeding sassy. He had loose stools that I assumed was a result of that. However, the loose stools continued. They formed up a bit with the help of pumpkin but never went away. After posting on here initially, I brought a stool sample into the vet and was told it was fine.

However, the loose stools continued and increased- I believe sassy may have been having them as well. This made me think parasites even though the stool sample was fine and the kitten has already been dewormed twice before coming in my house. I did some research and decided to try food grade diatomaceous earth to see if it helped. I put both cats on it once a day (and have since started my dogs on it as well). I did a regiment of 10 days and for those 10, blissful days, I had little to no loose stools to deal with and lots and lots of formed ones! Yesterday was their first day not getting DE at breakfast, and this morning, I found a nice, wet, loose stool in the litter box. It was a definitely Severus's because he does not cover his poop.

So I guess I'm hoping you guys could give me some thoughts. Should I put him back on DE? I've heard it's okay long term and that some people aff it daily, always.

Could it be the food? That's what the vet thought- she said that many cats have trouble with grain free and to put him on a cheaper food.

I currently feed them a mix of whole earth farms grain free kitten, nutro grain free kitten and nutro grain free cat. I have the foods mixed together in a big container and they get canned food, mixed with the dry food, a bit of water and a probiotic twice daily. I leave hard food out inbetween. I've tried so hard to get them the best within a price range I can afford. Should I try a food with grains like my vet said? Maybe he just needs more fiber and that's why the de worked? Should I just add de back in since it was working so well?

He's playing and acting normally.

If the DE is working, and you think it's safe to give everyday, then why not. 

But it is definitely true that some cats need more fiber than other cats.  And it  is also true that some cats have sensitive digestive tracts and certain foods simply don't agree with them.  Maybe Severus is one of those cats who can't eat fish, or can't eat peas, or whatever.  OR, if they both have lose stools, maybe they have one of the OTHER parasites than a normal fecal float doesn't pick up, like T.Foetus.  There is another test that detects some of the less common parasites called a PCR,  It costs more, but might be worth it if it detects something else.  And if it's T-Foetus, there's only one drug that I know of that will eradicate it.

So....there you have it (my take on the situation only, for what it's worth)