Tiiny bubbles in my water

[paul7475]

I have a 9 year old Apec RO system. I also have a water softener. I have been pretty good about changing the first 3 filters since installing the unit. Earlier this year the water started having many tiny bubbles in it and there was a small bubble slick floating on top. The TDS went from the teens to the low 40s. Don't remember what the supply TDS was. Seeing all of the bubbles and the bubble slick I decided to replace all of the filters. Currently the RO TDS is in the high 30s and the supply TDS is in the high 300s. I replaced the filters several months ago and I still have tiny bubbles and a bubble slick floating on top of a glass of RO water. The water seems to go stale pretty quickly too. When first installed the RO water tasted wonderful, didn't go stale and was crystal clear. Any thoughts?

[Alex]

I am not sure how many filter stages there are on your Apec RO system. It is good that you keep up maintenance on the first three filters, but have you changed the RO membrane filter?

The RO membrane will go bad over time (1-3 Years), and will degrade faster depending on the water quality. Water hardness minerals and Hydrogen Sulfide (rotten egg odor) will ruin a membrane VERY quickly.

The membrane should also be changed when the TDS reduction is at or below 90-95%.

What is the model number of your system?

[paul7475]

It is an RO-45. It is a 5 stage system. I replaced all 5 filters recently. First time for the ro membrane and the 5th stage polishing filter. With the TDS of the supply water of about 380 and a TDS of the RO water at about 38. Those numbers are after changing the filters.

[Alex]

You do need to flush the system for two to three full tank fulls after a filter change. The filters that you install will be full of air and will be pushed through the system and into the storage tank.

After the tank has been flushed you shouldn't notice any bubbles in the water and the TDS should be normal. Bubbles in the water is especially common when replacing carbon filters.

Apec RO-45 Filter replacements:
1st stage - Pentek P5 - 5 micron sediment prefilter
2nd Stage - Pentek EPM-10 - 10 micron carbon block
3rd Stage - Pentek EP-10 - 5 micron carbon block
4th Stage - TW30-1812-50 Membrane
5th Stage - CL10RO - 1/4" - Threaded 5 micron post filter

[paul7475]

After changing the filters I flushed 1 tank full of water. Since then I have used at least 10 gallons of RO water. How would flushing more water help?

[Alex]

The air that is in the pores of new filters will be displaced as the water saturates the filters or membranes. The bubbles will disappear once all of the air has been replaced by water.

The time required for all of the air to flush out of the system varies with different kinds of filters, membranes, systems, water characteristics and frequency of water use. Typically it should diminish within one to two weeks. This is a very typical process and is nothing to be concerned about.

Has the bubbles diminished with more uses?

[pawaterguy]

It could be as simple as soap on the glassware that wasn't rinsed off properly due to using too much. Do you wash by hand or use a dishwasher?