Welcome to our forum.
As to the amber fluid - it is a strong acid. Nitric Acid to be exact. I should be flushed out from time to time. The easy way to do this is to take the end of the tube loose at the ozone box and stick it into a cup of water. Let the spa draw it into the tub. Don't put your mouth to the tube to blow or suck - it can hurt you.
The new filters used on the Vista - will they work better on my landmark as the " old " one and What about the pressure on the jets ?