When using fertilizers like Nucleus 0-0-21 on the lawn the water is merely a carrier used to distribute the product evenly. While in most cases you only need 1-2 gallons of water per 1000 sq/ft, if you happen to have a really dense, taller turf you may require a higher water volume than someone else to make sure it gets sufficiently covered and moved over the whole treatment area. The water is whatever is best for your yard and we suggest somewhere between 1-2 gallons of water for whatever mix rate you use per 1000 sq/ft.
As long as both product labels are followed regarding rates you can mix Nucleus 0-0-21 with other products such as liquid iron.
In any mixing operation, product should be introduced in the following sequence:
Compatibility tests are always recommended prior to preparing a spray mixture of Nucleus 0-0-21 with other products.
There is no need to use a surfactant with Nucleus 0-0-21, although you can add a surfactant if needed for other products in your mix.