Hi,
See the copy below of our post on 28 March on the Merlin. It suffers a problem, which we have overcome with our Wizard, of sending to waste over three times the water it produces, and offers only 93% average rejection of impurities. The Wizard also comes with an in-line dual TDS meter.
The Merlin is stated by its manufacturer GE to be designed with TDS rejection between 90 and 95%, with a quoted average of 93%. Interestingly, it’s also designed with a small optional extra “flush tank” (Part no. 1261345), and already has a Speedfit connection in the manifold to accept this flush tank. The purpose of the flush tank is to eliminate the problem that commonly occurs in a stop-start situation where the first water produced by an RO after a stoppage has much higher TDS than after it has settled down and been running for a few minutes (often referred to on this forum). This flush tank should greatly improve the 40ppm TDS that is currently being obtained in sham33’s situation. I don’t think that the extra prefilter mentioned will improve the TDS, although it should cerainly extend membrane life.
On test in early February, with our modification to the Merlin, we produced 2138 L/day at 19ppm TDS, from Southport tap water at 280ppm TDS, at 11 degrees C, and a pressure of 53psi (3.5 bar). Our waste : product ratio was 1 : 1, far better than the unmodified Merlin, at 3.25 : 1, and this may be an important consideration if your tap water is metered.
Yours, Andrew