Cleaning membranes

[Brent]

Well after a few days running the Merlins and each day getting better, today I went backwards.

Don't know if it was self inflicted or a design suitability issue. I forgot to flush them last night so they sat with 6% in them all night growing little ugly things. Today when I started I ran them a few minutes to a dump jug to flush out any foul flavours, but the permeate flow was down to 1/2 of what it was the day before. The concentrate flow was good so the filter is not plugged.

What do you clean them with?

GE just wants you to buy new ones. I see some people use a soap and some use an acid.

I'm going to bring them into the house tonight and flush with plain water anyway.

Do I need a rush trip to the local maple dealer tomorrow AM ???

[Gary in NH]

Brent,

In the absence of soap you could try getting some warm water and recirculating it continuosly through the system to see if it will flush out whatever has accumulated on the membrane. Generally, cleaning is done with a high pH solution for cleaning organics like sap and low pH solution for minerals. A solution with a pH of 11 should do it. You could use sodium hydroxide (caustic soda) as an alternative to RO soap. You would need a pH test kit capable of reading above 11 to take out the guess work of how much caustic to mix with the water. If you use caustic soda be extremely careful. Rubber gloves and eye protection are strongly recommended as well as a source of water for dilution. After recirculation you will need to flush the RO's until pH is the same as feed water supply. A pool supply place may have the chemicals and pH test kit.

[Brent]

Thanks Gary.

I hope I can get them cleaned and performing again. I may have screwed up and invalidated the "GREAT MERLIN TEST RUN" by not cleaning them. Not sure how many more days of run we'll have to finish a decent test.

[Gary in NH]

They should clean up fine. They haven't seen a huge volume of sap and the pressure has been low. Once you are done you may as well use one of those RO's for your drinking water until next year!