Hi starting tds is around 350 sometimes up to 380 tap pressure i would say around 45psi ,ratio not sure as i turned the waste dial gauge to read 20 lpm and thats about the the lowest i could get tds ,,at that setting ,if i turn it down anymore tds goes up ....and the same if i turn it up .....
It looks like you have throttled your water to waste to give you the optimum preformance from the membrane.
Your r/o is running at an efficiency of around 94%. In other words, its removing 94ppm of every 100ppm of water it filters.
One supplier once told me that 94% was considered the time to replace the membrane. In the best situation it should be between 97 and 98% efficient.
Do you know how old the membrane is?
As Nathan has said, tap water pressure at the r/o is very important as it effects how well that membrane performs. However, adding a booster pump won't help much if the membrane is 'worn out.' You do need to know what your water pressure is as well as what your flow from the hose is in liter per minute as those are important considerations. Screwfix, Toolstation and large plumbing outlets will sell pressure gauges to test water pressure.
Now, here's the bad news. Brodex supply their systems with one single prefilter which they fit a sediment filter into. They don't add another filter to remove chlorine from the water. Chlorine causes premature membrane failure which every supplier knows.
Brodex also know this but chose to continue with this practice as they have another bite at the profit cherry when they advise a new membrane is required. They say that there isn't enough chlorine in our water to damage membranes.
So the first thing I would do is check to see what filter is inside that prefilter. If its just a sediment filter, then replace it with a carbon block filter such as a Fiberdyne filter that suffices as a sediment and chlorine removal filter. In time I would buy a second prefilter and have a separate sediment and then Fiberdyne carbon block filter in the second housing.
I have an Axeon HF5 membrane in my r/o as it works better at lower water pressures than the HF4. Our water pressure is 50psi and our membrane is running at 97% efficiency. Its 7 years old in September. We have 13lpm of water from the outside tap. I don't run a booster pump.
Now here's another story that was reported by one of the other suppliers. He has seen Brodex di vessels come in with the O ring missing that seals the tube into the head of the filter. This means that not all the resin is used in the di vessel to polish off all those remaining impurities in the water. Checking and adding an o ring won't help your membrane situation but will improve the efficiency of your di vessel. Your resin will last longer.
I've had a very bad experience dealing with that company (Brodex)and I will never deal with them again - ever. If you need stuff then look to Gardiners and Daqua as they are genuine suppliers. Fiberdyne prefilters from GAPS water.
