diff --git a/public_html/lib/order_lib.php b/public_html/lib/order_lib.php
index 5c61b95..fc86f2d 100644
--- a/public_html/lib/order_lib.php
+++ b/public_html/lib/order_lib.php
@@ -362,7 +362,7 @@ $(document).ready(function(){
             <tr>
               <td class="td-title-info">Sludge</td>
               <td class="td-text-info">
-                <input type="text" id="d_sludge" name="d_sludge" value="<?=$rt_sludge['c_sludge']?>" placeholder="50">
+                <input type="text" id="d_sludge" name="d_sludge" value="<?= (empty($d_sludge)) ? $rt_sludge['c_sludge'] : $d_sludge ?>" placeholder="50">
               </td>
             </tr>