Back to the aero discussion....
Ive given up on AA. The cost of a quiet air compressor combined with the $$$ mist heads is jut not gonna happen. Plus, the space for a compressor, an extra air tank, and an accumulator will cause space issues that will be very difficult to handle.
So, Im gonna try HPA and see how cheaply I can do it. Unfortunately, there are not a lot of components that can be built DIY.
I agree about the accumulator being a potential bomb. There is also the problem that compressed air will be in contact with the nutes all the time which could make fizzy water droplets and get absorbed over time. So Im gonna need a bladder type tank.
I found a thread where one person was using an espresso machine pump to drive his HPA setup. He had it operating for two years - until he let the rez run dry and melted the pump I would be ok with 2 years of opperation for the low cost compared to diaphragm pumps.
Ive been reading HPA threads non-stop for the last 2 days and Im starting to get a handle - I think - on how the system needs to be setup, inexpensive components I can use, etc. One thing I do not have a clear idea on is how large the root chamber needs to be for one or two plants.
Do you have any suggestions on how to decide how big the chamber needs to be? Most everyone agrees a 5 gal bucket is too small, and the chamber needs to be fairly tall - but how tall and how wide?
I know I want to use the idea from a guy named Atomizer on RIU. He suggests using a fabric, or at least fabric lined, chamber. He likes the fabric from trampolines, but I am thinking of doing it his way using extra large, fabric smart pots.
The idea is that the roots will grow over to the fabric, and then when they try to grow through the sides or bottom, they get air trimmed automatically. Plus, the air circulating around the outside of the chamber will automatically help keep the root zone cool through evaporation of the excess water on the fabric.
This is especially important for the bottom of the chamber. If roots get to the bottom, they will tend to matt up and trap water or they will seek out any standing water from over spray. Those roots will not be true aero roots if they get into standing water. A fabric bottom in the chamber will allow any excess spray water to go through the fabric and will not make puddles. You need a second container below that to collect any runoff, but if things are dialed in closely enough, ther should be almost none. Thats why this is such a good way for doing drain to waste - there is almost no waste.
But I am still not clear on how large to make the chamber....more reading to do...