I have a large bucket of 3" Tri-chlor tablets that I've been using in the pool. I have no idea how old they are - we got them and the pool from the previous home-owner. I've been using them but I've also had to add bleach almost nightly to maintain a free chlorine residual (even though the tab floater is set to max). Today I decided to try to determine if the Tri-chlor tabs are actually doing anything so I dropped half a tab into a cup of water and let it sit. About 9 hour later I tested the water with my Taylor DPD test kit and got some really weird results:

- Added 5 drops of R-0001. No color change, none expected.
- Added 5 drops of R-0002. Each drop turned pink as soon as
it hit the water but then immediately faded to clear. After
swirling, the solution was still completely clear.
- Added 5 drops of R-0003. The entire solution turned a very
very dark murky brown.

There was definitely a smell of chlorine so I think the tabs must be somewhat effective but the above results have me scratching my head. Would this be expected if there was much more chlorine in the water that the test was meant to measure?? Or if the tabs are bad?

Thanks in advance!