The new urine/spray removal products have enzymes that break down the cat markings.Gone are the days of throwing away carpet because a cat had an accident.It's a new day.

Dear George P and all the gang on BPI help you are doing well wherever you are ans whatever your endeavors might be God Bless you all as the end of the year draws nearIn a word George ,grid strainers are great and should work FINE ,,,,As long as you have a CLEAR RUNNING DRAINLINE.If the particular drain is running slow you have what they call a PARTIAL STOPPAGE,,soon to become a FULL STOPPAGE.The simple answer is to have a competent experienced plumber cable out you drain line with a 1/4" to 3/8" cable.In a rental property you should do this as a preventive maintenance every 4 to 6 months.An excellent product to prevent stoppages is BIO CLEAN it is an excellent non toxic dry enzyme product you use once a week last thing at night.You can buy it on amazon dot comHope this helps gangI wish you all a happy Thanksgiving and remember I am here for you all with these crazy plumbing issuesDave Doyle Los Angeles

I soaked it liberally with a good quality enzyme cleaner, but it didn't do much, I then put several coats of BIN primer on it, but if i put my nose down to the floor I can still smell it, however the room doesn't smell any longer. 

Treat it front and back with enzyme type treatment that you can get from a supply house.

The Zif wall paper remover enzyme works well and can be purchased at Home Depot.

It is an enzyme-action product that breaks down the urine into components that do not have an odor.

Then you spray the concrete slab with an enzyme that eats the urine out of the pores.

As said, I tried everything that I could think of (ozone generator, leaving windows/doors open for days, pouring bottle after bottle of cat urine enzyme cleaner, scrubbing the floor, and other solutions).

They often sell a product that will neutralize cat urine.Clean with a vinegar solution first, then treat with the enzyme cleaner.

Spray with a probiotic enzyme....let set for 3 days than ozone overnight with all cabinets open and air conditioner on to pull thru ductwork.