Hi

IâÂÂve been growing hydroponically in 100% coco for about a year now and IâÂÂm planning some changes to my system and was hoping for some advice..

Background:
1) Currently growing 5 rose bushes, 3 citrus trees and 4 pear trees using a drip system
2) Currently I think my containers are too small

In a few months I am moving house and am planning to set things up a little differently when I do. The changes will be:
1) IâÂÂve ordered 7 huge containers (1.75m L x 40cm W x 50cm H)
2) 5 of the containers will hold 5 Rose bushes each (so increasing total # rose bushâÂÂs to 25)
3) 2 of the containers will be used for miscellaneous herbs and vegies (undecided about exactly what)
4) The trees will be put into soil and removed from the system

In my current system I have noticed that 100% coco leads to a huge amount of nutrient wastage when I flush the system. Because it holds so much water, nutrients accumulate there. When I flush I remove those nutrients and they are wasted, and then during the next few days I need to add a lot of nutrients to my tank as they build up in the medium again. Because my new system will represent a BIG increase in the total volume of media used, I am concerned that this wastage is going to skyrocket and my hobby will become too expensive. For this reason I am considering mixing the coir with something that holds less water such as perlite in order to reduce the amount of nutrients that are held in the medium. My questions are:

1) Am I on the right track or am I making some erroneous assumptions in what I have said above?
2) Other than Perlite, what other options could I use to mix with the coir (particularly $ saving options!)
3) How far can I go? (e.g. 30% perlite? 50% perlite? 70% perlite?)