Grant - Don't lose faith and keep your chin up!

There are multiple odor products out there. If this one didn't work for you try another.

I don't do urine jobs any more but when we did I used enzyme products. Last one I did though was at my own house. Used Vacaway product and it worked great.

Some of these products have a shelf life and are particular about storage. Was the product you used older?

Do you have a waterclaw?

http://www.interlinksupply.com/index.html?item_num=AC004+++++++++++++++

I have used Bio modifier from interlink  and a water claw to the happiness of some clients.

http://www.interlinksupply.com/index.html?item_num=CD01GL++++++++++++++

I found using the water claw was way bonus on extracting even through the pad.  But you must also be prepared for the fact that some pee problems cannot be treated from the surface only.  Some big pee problems need the carpet pulled the flooring treated and then painted with Kilz to block any more odor from coming out and then replacement of pad and relay the carpet.    Rare that a customer wants to pay for it since fluffy is just gonna **** there again next week. But with that being said it is up to the customer at that point.

Absolutely true about sub floor and pad.

Sometimes you need to pull carpet, remove pad and seal the floor.

The one thing about UV is you can't tell how much urine or how long the animal has been using the area. Most times it isn't a one time thing.  The carpet may have been cleaned in the past which would also remove enough urine that the black light doesn't detect what's under the carpet and you end up missing a spot.

So you start out with the simple topical treatments and tell them it could be as involved as pulling up the carpet, cleaning, replacing pad and sealing floor. If the carpet is a real rag I would tell them to pull it all out and seal the floor. Then buy new flooring.

I use petzone in my house.  Works good, also have the hyracide  in a bottle, its the same stuff that is in petzone.  (Not sure how to spell the hydracide). 

Grant - Urine jobs are as much art as science. Sounds like you are doing everything right.

Just like the rest of carpet cleaning you go until you think you've got it. If you miss anything or the treatment doesn't get where it needs to go then you will still have some odor.

I always told my customers it might take more than one treatment. If you only have an occasional situation like this than I think you are doing great. 

You can also use a good wet  vac with the water claw. Just pour a pitcher of water on it at a time. to rinse.

   I use the Pro's Choice  OSR,  and I had one that was NASTY, NASTY,NASTY with urine.(Did I mention NASTY)    It did take 2 treatments but came out .  I was sold at that point..      Took carpet and put it in a pool I made with tarp, osr treatment then steamcleaned and customer was V. happy with results.       

Odoban makes a pet floor cleaner works pretty good on carpet as well. Look in home depot