hi fellas
im retiring my trusty old merlin soon and upgrading to a 40 40 , ill most likley buy it from gaps , advice please they have about 6 different ones . ie types of main filter
size of pre filters 10 or 20 inch etc
can you give me some feedbck on
tds of finished water ... do i still need a di
what % waste
amount of finished water per hour
and any other info would be appreciated
regards john
Too many variables for an accurate answer.
June at Gaps is a very good advisor. She will sell you the right stuff for your individual needs even if it means taking less money from you.
However, if you want a 4040, you would probably be well advised to get an HF5. Apparently they work better at lower water pressures. So the HF5 covers more varieties in water pressure. This is probably a good idea at the moment particularly if you are in a drought area because the water companies tend to drop the pressure in droughts - to reduce the negative effects of leaks.
As for pre-filters, I prefer the 20" ones. They cost more than 10" ones (as do their housings) but you only need to change them half as often.
As for waste pure ratio, it's better if it's adjustable and I set mine at around 50/50. I turn the waste up full twice a week for 15-20 minutes to flush the system. Apparently this lengthens membrane life.
Production: Many variables here. Depends on water pressure, mains quality, time of year (temperature), what ratio you use for the waste/pure, age of pre-filters.
To give you some idea, when the membranes and pre-filters were new I got the following:- Setting waste/pure was 50/50. Water pressure 35-40PSI. Normal spring temperature. This gave me about 100 litres per hour of pure at 007 TDS. Much better than this is possible with decent pressure. As the pre-filters age and the temperature cooled in winter, it became more like 015 TDS at 50 litres per hour of pure. So circumstances can make a hugs difference. Production seems to rise when pre-filters are changed. Also, production decreases a bit as membranes age.
BTW. I would recommend using resin just in case. At the moment, water pressures are liable to drop in many areas meaning that TDS out of the RO should increase.
BTW. Forgot to mention. Tap TDS is about 200 on my supply.