diff --git a/vega/build_config.py b/vega/build_config.py
index ea295ee..8c6c133 100644
--- a/vega/build_config.py
+++ b/vega/build_config.py
@@ -72,6 +72,7 @@ def __init__(self, options={}, overwrite=False):
         self.options['use_metal_autos'] = options.get('use_metal_autos', True)
         self.options['new_metals'] = options.get('new_metals', False)
         self.options['metal-matrix'] = options.get('metal-matrix', {})
+        self.options['use_metal_bias_eta'] = options.get('use_metal_bias_eta', False)
 
         metals = options.get('metals', None)
         if metals is not None:
@@ -664,7 +665,10 @@ def add_bias_beta(new_params, tracer, bias_beta_config, bias, bias_eta, beta, gr
         # Metals
         if self.options['metals'] is not None:
             for name in self.options['metals']:
-                new_params['bias_eta_{}'.format(name)] = get_par('bias_eta_{}'.format(name))
+                if self.options['use_metal_bias_eta']:
+                    new_params['bias_eta_{}'.format(name)] = get_par('bias_eta_{}'.format(name))
+                else:
+                    new_params['bias_{}'.format(name)] = get_par('bias_{}'.format(name))
                 new_params['beta_{}'.format(name)] = get_par('beta_{}'.format(name))
                 new_params['alpha_{}'.format(name)] = get_par('alpha_{}'.format(name))
 
diff --git a/vega/parameters/default_values.txt b/vega/parameters/default_values.txt
index 12f091b..dcce936 100644
--- a/vega/parameters/default_values.txt
+++ b/vega/parameters/default_values.txt
@@ -40,9 +40,9 @@ bias_eta_SiII(1193)             -0.02       0.0         0.001
 bias_eta_SiIII(1207)            -0.02       0.0         0.001
 bias_eta_SiII(1260)             -0.02       0.0         0.001
 bias_eta_CIV(eff)               -0.02       0.0         0.001
-bias_SiII(1190)                 -0.2        0.0         0.001
-bias_SiII(1193)                 -0.2        0.0         0.001
-bias_SiIII(1207)                -0.2        0.0         0.001
-bias_SiII(1260)                 -0.2        0.0         0.001
-bias_CIV(eff)                   -0.2        0.0         0.001
+bias_SiII(1190)                 -0.5        0.0         0.001
+bias_SiII(1193)                 -0.5        0.0         0.001
+bias_SiIII(1207)                -0.5        0.0         0.001
+bias_SiII(1260)                 -0.5        0.0         0.001
+bias_CIV(eff)                   -0.5        0.0         0.001
 desi_inst_sys_amp               0.0         1e-2         5e-5
diff --git a/vega/templates/parameters.ini b/vega/templates/parameters.ini
index 375336f..684a3a3 100644
--- a/vega/templates/parameters.ini
+++ b/vega/templates/parameters.ini
@@ -62,23 +62,28 @@ dnl_arinyo_kp = 19.47
 
 # Metals
 bias_eta_SiII(1190) = -0.0026
+bias_SiII(1190) = -0.0052
 beta_SiII(1190) = 0.5
 alpha_SiII(1190) = 1.
 
 bias_eta_SiII(1193) = -0.0012
+bias_SiII(1193) = -0.0024
 beta_SiII(1193) = 0.5
 alpha_SiII(1193) = 1.
 
 bias_eta_SiIII(1207) = -0.0037
+bias_SiIII(1207) = -0.0074
 beta_SiIII(1207) = 0.5
 alpha_SiIII(1207) = 1.
 
 bias_eta_SiII(1260) = -0.0023
+bias_SiII(1260) = -0.0046
 beta_SiII(1260) = 0.5
 alpha_SiII(1260) = 1.
 
 bias_eta_CIV(eff) = -0.005
-beta_CIV(eff) = 0.27
+bias_CIV(eff) = -0.01
+beta_CIV(eff) = 0.5
 alpha_CIV(eff) = 1.
 
 # UV model