We have standard housing wrenches(used for standard 10" and 20" housings)reverse osmosis wrenches to help you with loosening your filter housings.  Never use these wrenches to tighten your water housings. Over-tightening can damage your O-rings, causing leaks and make re-opening almost impossible. When you're done with your housings you should hand tighten only. If your filter housings are really stuck, you may want to use two wrenches together, otherwise you could break a single wrench.