Help With Kentia Palms

[Rosscat11]

Hello there! New member here. I would love some advice on how to properly care for (or save) two new multi-trunk kentia palms that I recently purchased. This may be a long post, so I apologize. About three weeks ago, I planted two very health looking kentia palms from 15-gal.plastic pots into very large planters. They are starting to show signs of shock. I have already lost one pair of palms that were planted in the same pots. I just can't figure out what I am doing wrong. My planters are 3 feet tall and 3 feet wide, so plenty big enough to hold these palms for a few years. I filled them with about 1 foot of silty, clayey soil from my yard on the bottom and the rest with a combination of peat moss, perlite, sand, cactus mix. All well draining materials. I am watering them every two to three days and checking the top 8 inches with a moisture meter. I installed a one-inch pvc pipe to about 14 inches in each planter in an attempt to get some water to the lower roots. I have seen this done with other palms. The very bottom fronds have turned brown and a few of the other fronds are browning on the tips. When I removed them from the plastic pots, I did not loosen the root ball because I read from what seemed to be a legit source that it wasn't necessary. I love in Orange Co., California, near the ocean and the temperatures have been perfect for transplanting. Any advice would be greatly appreciated. These palms are expensive!! Thank you.
If a photo would help, I can upload later.

 

[cpp gardener]

I hope the palms are still alive.
Are they inside or outside? Do the pots have holes in the bottom?
If they are outside then you are probably over-watering them, especially if they don't have drain holes. If they are inside you are definitely over-watering them.
Putting the yard soil in the bottom is a bad idea, it only makes the drainage problem worse. Normally outside you should be watering about 1x per week in the summer and once every 2 weeks in the winter. When you water them you should soak with enough water to have a small river come out the bottom, then you'll know they are completely wet top to bottom.
If they are inside, you probably only need to water them about 1x per month if you water to the point that water comes out the bottom.
If you have more specific questions there are a number of Armstrong Garden Centers near you and they are very good at helping figure out what's going on.
Hope things are working out OK and let us know how it's going.