Which test kit?

[rdeis]

What are the favored brands of test kit for good results?

I have the Aquarium Pharm. "dry-tabs" brand of Nitrate, Nitrite, Amonia, and wide range PH, and also their KH GH.

What's missing for plants?

Phosphate, I think, maybe a higher precision pH, and TDS? (Or is the GH/KH enough?

[angel12]

in regard to plants a Phosphate test kit is probably the most important is this is related to algae growth a high phosphate level can be linked to outbursts of Alage - you could also get an Fe kit (iron) as this is a micronutrient that Plants need and it is not a static element
in other words it is not an element the plants can source through the Substrate it is mobile

HTH
:)