supplementing

what time of supplementation should I use for a 29g reef tank?

What is your system lacking?

Yep,you need to know whats low...

If needed I dose calcium,strontium,magnesium,iodine,buffer and trace elements but rarely.Regular water changes will replenish them.This is on a LPS/softies tank with no SPS.

well all my water parameters are looking good
Temp - 78.5(lights off) 79(lights on)
SG - 1.0235
ammonia - 0
nitrite - 0
nitrate - 5
pH - 8.4
dKH - 11.4
Caclium - 400ish
PO4 - .1 - .2

I guess I was really wondering more about trace elements.

"If it ain't broke don't fix it" is the way I look at supplements. If you see something wrong with your tank or your animals then you may need to start adding things, but it is difficult to test for trace elements, so it's hard to know if you even need to add any. Plus, your tank can OD on additives.

Looks to me like you really dont need at add anything.
Just do your regular water changes and you should be good to go.

however if your going to grow corals you could benefit from kent marine reef starter kits they contain calcium, iodine, strontium, molybdemim, amonia ditox, and pro buffer dkh that should do.

if you are going to add trace elements be sure that you have test kits for them. Too much iodine etc in the tank can cause a crash.

Is there a test kit for trace elements?
I look at it like this,calcium consumption goes with the depletion of other elements such as iodine,strotium.molybenum.etc.If and when my calcium was low then I would use supplements to replenish it and other elements.But like I said earlier that I rarely dose because water changes was enough to replenish those elements.

There are test kits available for them. Iodine is one of those tricky elements where too much can be a very very very bad thing.