Replying to Pressure Washer Hose Expensive!

Im in the process of building a Hago external mix gun into a 4' PVC drain pipe tower. Im using 2 4002 jet nozzles and I just ordered some different Hago nozzles from them. Its going to use a 6' Stainless pipe nipple between the two upper 4002's and then the rest will use high pressure hose. The problem is that hydraulic hose is very expensive. Is there any kind of a substitute for it to run from the pressure washer to the tower because we can buy the stuff for inside the tower but the problem is the cost for 25 feet or hose for outside. Someone said they used air hose I think but wouldnt that break?