MikroTik

Mikrotik and apple issues
I have a client that live in an old farm house.
The bedroom wall is almost 1m thick and so I decided to put one rb951Ui-2hnd in the bedroom and another one in the centre of the house.
I have setup wifi on using same SSID, WPA2 aes but different channels.
All connected devices are apple iphones and ipads.
The owner of the house uses speedtest.net a lot and constantly complains to me about poor speed.
I have tried tweaking both routers by setting Hw. Protection Mode to CTS-TO-SELF, setting FREQUENCY MODE to regularity-domain, only set to use chain 0 instead of chain 0 and 1.
Today I reset the wireless interfaces on both routers to default and setup the SSID, WPA2 aes and regularity-domain but I set the tx power to 13(20 miliwatt)
Any advice to what else I can set to resolve this issue for good?
Also I would like to know is it better to set channel to auto select?

PS: Sorry for bad english

Reset wireless interface to default and frequency to auto.

What are the exact signal levels in the router?

If the client is complaining about speed, how sure can you be it is due to the WiFi? How is the backhaul (ADSL, cable, fibre, etc...) How is the quality of the ISP? Overbooking factor, time of day when speed problem are seen etc....

Do not blame directly to the Mikrotik, investigate from the back end first.

Normis at the moment I have set data rate not to go higher that 18mbts. Also changed tx power back to default. I notice that all other devices usually connects well. Don't know if it is because he uses iphone s6.

Here is a printscreen of what it shows.

Solved by installing external antennas on the RB951 and also reset wireless to default.