QRCode Error Correction Level

Either set height property in codebehind .cs file

BCSBarcodeCtrl1.Errorlevel = 1;

Or add a tag directly

< img src="barcodesoft.ashx?s=qrcode&qe=2

< img src="barcodesoft.ashx?s=qrcode&qe=3

int Errorlevel

Default value of Errorlevel property is 2 (ECC Level M).
You can set it to one of four levels listed below: L(1), M(2), Q(3), H(4).
Other value will be reset to its default value.

Value ECC Level
1 L
2 M
3 Q
4 H

You can also setup Errorlevel property through URL by setting "qe":
<img src="Barcodesoft.ashx?s=qrcode&TEXT=1234&qe=2>