If your plants begin to decay, this will produce excess ammonia in your tank and deplete the oxygen in the water.
(your plants; begin; ) (your plants; to decay; ) (this; will produce; excess ammonia; L:in your tank) (this; deplete; the oxygen; L:in the water)
your plants your plants this this
begin to decay will produce deplete
excess ammonia L:in your tank
the oxygen L:in the water