Can't comment on what is right for your diet, but I do know about ketostix so since nobody else has replied..........
ketostix don't test for ketosis. This is something that lots of people think, but they aren't for that. They test for excess ketones.
Now...some people make more than others (nothing to do with more fat loss or anything), they just do and may have excess ketones. Some people use their ketones very effectively and may not have excess ketones. Either way, they could be in ketosis.
If your test is coming out purple, two things are likely to be happening. You aren't drinking enough (excess ketones aren't being diluted so showing a strong result), or your just making lots of ketones.
Doesn't have anything to do with the level of ketosis or anything. Just check you are drinking enough and if you are, ignore them
personally, I'd ignore them. I lost 8 stone on a keto diet and never once even got a pink, let alone a purple, yet I was definitely in ketosis