I purchased two Diawa Tatula TWS Sv reels and it seems as the drag won’t tighten down like my Diawa fuego reel. When I use it for frog fishing the drag slips on hooksets. Anybody have this problem? 

use mono backing behind the braid. Could be slipping on the spool. 

Good advice.. thought it was ghost slipping, but I noticed the drag doesn’t get as tight as my other reel and think it’s just a problem with the drag. 

If you're certain that the line isn't slipping on the spool, then maybe there's some grease in the drag stack? I've a couple of SVs and a few CTs, but no Fuego, so I don't know whether they're any different (unlikely), but you'd struggle to have the drag slip on any of them if you tightened the drag down. I'd want to be really certain it wasn't slipping line before I started looking for mechanical issues though. Very unlikely you bought two reels that are malfunctioning.

This can be another example of a factory defect coming straight from the factory and also an example of how it can happen to any manufacturer no matter how much you pay for a reel or what brand their can always be a factory issue and if this is the case I suggest you return it for an exchange or call customer service.

I fished my CT Type-R very hard in the weeds this summer, and one day while frogging, I lost a fish on a hook set and thought the line snapped. Well it actually didn't break off and the spool slipped while engaged. The spool kept slipping even while the drag was set all the way down and I sent it back to Daiwa for repair. On the return invoice (free under warranty), the part they replaced was the Spool Assembly which is about 8 things. Part Z02-1543.

Thanks for all the feedback on this issue. Today I drove 2 hrs to my local Cabelas and gave them my reels for inspection in the fishing department. What we found out is the place that put on my power pro braid never tied it to the spool.. “yikes”  the guy also never used mono first, he used straight braid.  So all this time I thought my local sportshop put the line on right, until we found out the truth at Cabelas today. Problem was solved by them taking the line off the reel and putting it on a empty spool. Then they used 4lb mono for a few turns and put the braid back on the spool. So now my drag is solid as it should be..Quick fix!!! No problems with Daiwa..