sorry, i meant perlite.

50/50 mix of perlite and peat moss.

i made a brew of 50/50 peat and perl it looks great but very light compared to the bog they were in stock from nursery im hoping it will be cooler and better airrated than sand/peat, i put moss on top carefully avoiding the little crowns i left a little exposed and then very gently watered them the peat seemed to wana wash from the perlite? would this be a problem will the peat just wash from the perlite over time? and will it wash from the perlite right through the mix?

No top dressing needed. Don't worry about it. The sarrs should be sitting in a water tray with about an inch of water in it. Top watering isn't needed although once in a while it's good to do to get air flowing through the soil.

How often should I replace the the water

as soon as it is almost out, sarracenia absolutely love water, you can flood them with water as long as you don't let the water level rise above the plant. make sure it is getting six or more hours of sunlight a day.