Hi Sandy, and welcome back!

I would leave your TA alone unless you having problems keeping your pH steady.....80 is just fine. At your CYA level of roughly 30, you're kind of on the edge of the envelope if you keep your FC at 3--I'd push it up a little higher to maybe 4 or 5 just to make sure you don't have problems. An alternative to that would be to maintain it at 3, but shock it on a regular basis.

As far as your DPD powder goes, it will change colors...it should have been white when you bought it, and the directions say that you should replace it when it's medium gray, but I have used the powder until it's dark gray (as long as it's not clumping) and it's been fine. If you're storing your kit in the ziploc bag away from heat, light, and humidity, then you can probably go 2-3 years with the reagents with no problem.

Janet