Archive by month

It has been about two years since we purchased an entry level RO water maker kit (Aquatic Life RO Buddie 4-Stage Reverse Osmosis Deionization Water Filter System RO/DI Filtration Units for Aquarium, 50 GPD) to make "distilled" water for some ultrasonic humidifiers in our house.  This type of humidifier is capable of vaporizing the minerals in tap water which then deposit themselves in a thin film on everything in your house.  Using distilled water is hence required/recommended, and using RO water is good enough according to some people and to my experience.

So now two years later and a wild guess of 400 gallons produced, is it time to replace the consumables in my RO setup?  Here are the numbers:

In three minutes it produced 420ml pure water and 1450ml waste water.  Per hour that is 8.4 liters (2.2 gallons) and 29 liters (7.7 gallons).  Roughly 1:3.5 ratio which seems to be about expected.  I did the same calculations when new--of course I did not save them but from memory this was about the same.

Input water measures 279 ppm TDS and 4.3C temp.  Product water measures 0 ppm and waste water measures at 340 ppm.

My verdict: It is performing fine, I will replace the carbon and sediment filters as recommended, at a cost of $7 each.  Mainly this is to eliminate worry of chlorine damaging the membrane.

Some notes on the setup as seen in the picture:

• The feed tees off of the washing machine supply line.  And the dryer tees off of it too so there is a lot going on there compared to the average washing machine!
• The feed runs into a garden hose timer so I can set it to 45 minutes and walk away.  For the first year we had it connected to the faucet and would set a timer when starting it, so then have to go back and stop it.  This way we also have use of the sink.
• The assembly is mounted inside of the laundry sink.  This way if something leaks there are decent odds that it will not be a house-flooding occasion.
• Pure output goes straight into a watering can which we use to fill the humidifiers.  The waste line is tucked into the drain of the sink.

Update: after replacing those two filters, things seem a little worse.  In three minutes the numbers were 410ml and 1550ml.  I have no theories for this.  Certainly there is some measurement error but I think this would be at the upper bounds of error to be found in my methods.  So maybe.