Ro unit slow output | The Aquarium Solution

Ro unit slow output

Question:

i have just purchased and installed the above unit but have had the unit running for 6 hours and the output is just shocking? i have checked all fittings and are all perfect. have checked the flow restrictor and that is working fine and in the correct 90deg angle and when flushed it flushes fine. i have what i can only describe as good mains pressure and live in a modern house and connection is made from a split y connector on the washing machine terminal. as mentioned all check out fine but because there is no pressure gauge on these which i find quite unusual as this has great effect on the units performance as you will be well aware of i can not get an actuall reading which is very frustrating. i am getting only 2 ltrs of pure water every hour which would take weeks to get my 350 up and running not to mention the waste to pure water ratio! i am starting to wonder wheather i made the right choice with this and would greatly accept any help from you with this very frustrating issue.

best regards richard.

Answer:

Richard
Thanks for the email
It is unusual to get such low flow even at this time of the year and with "normal" pressure I would expect to get about 20 US gallons per day at these current water temperatures. This is about 3.1 litres per hour.

We supply a high quality Filmtec membrane and like all membranes the flow is quoted at 3.4 bar pressure and 25c temperature. See link below.

http://www.appliedmembranes.com/FilmTec%20Specs/TW30-1812-ALL.pdf

You will see that at 10c this drops from 50 to 20 gallons per day at a constant 3.4 bar pressure, is a 60% drop in flow.
My current water temperature is 7c.

If you drop your pressure from 3.4 bar to 2.7 bar even at 25c then you get only a 20% drop from 50 to 40 gallons.

We can therefore see that temperature has the greatest effect.

Getting back to your point about the gauge or lack of gauge, we have been at the forefront of aquarium RO sales in the UK for many years and have made a decision not to fit a gauge as they usually rust in a marine environment and cause people problems later. The gauge will tell you what the pressure is however there is little you can do about it once you have the info.
Instead we put the cost of the gauge towards supplying a top quality membrane, quick release fittings and supplying all of the parts to fit the unit whilst keeping the price reasonable fir the hobbyist. Look around at others and you will not see all of these features.

If you are really concerned about flow, as you will have the same problem with all units, then the best way is to fit a booster pump which will increase the pressure to about 7-8 bar and my experience is that you will get the full 50g.
I have 2 x RO 50 and can get more than double the flow at this time of the year however the one with out the pump is only producing 3 lts per minute currently.

If you need any more advice then please come back to me

Regards
Stuart