Both at once it quite okay. The ionic footpads cleanse the lymphs and the Hulda Clark e might leave some dead parasites there so it is actually quite a good idea to do both. Be aware that the foot pads work (obviously) on your feet but as well on other parts of your legs, back and body that need to evacuate toxins.
Beware sometimes they stain the bed linen, wearing socks over it will help.
My heavy metal contamination is very similar to yours.