I would suggest not installing a strainer. They have tended to cause me more trouble than they are worth. If the solids that you are like to see will pass through the pump, I would let them pass. I only use strainers for startup of brand new system and for towers where I know I have a history of scrap iron. In all other cases, if there is material present that will plug the strainer, then it plugs up, the pump runs dry and wrecks. If there is no material that will catch in the strainer, then I am just imposing a lower NPSH on my pump which can increase the chances of cavitation or other problems.