Gross sediment

[mike31154]

Can't beat a visual inspection when it comes to seeing if your sediment filter needs changing! That's a good reason to spend a few extra $$s for the clear filter housings rather than the white ones for sediment stages on your RO system.

As to what's normal, that will vary depending on each individual's source water quality and in many cases the time of year & as mentioned, if your supplier is flushing lines in the neighbourhood. It also depends on how much water you're producing during a given time period. While most of us likely produce about the same amount of water every month, I find a more accurate way to determine filter condition is by tracking the quantity or volume of water through the RO membrane, rather than by calendar. Since I use RO for purposes other than just my tank (making beer, wine, tea, coffee, soda pop etc.), there are times when I'll run the RO more often.

It's tough to provide advice on what's normal when someone says 'this is what it looks like' after a week or month, when one has no idea what the source TDS was or how many gallons were actually put through the RO system. Even though another hobbyist in your area might wish to give sound advice, that hobbyist may have a much larger or smaller tank than you and he/she may produce a vastly different amount of water in a given time frame than you.

Here's a screenshot of Excel spreadsheet I use to track my RODI system performance. In addition to the visual cue of the sediment filter, I use the pressure differential between a pressure gauge that measures house pressure & one before the RO membrane. This differential is a sure fire clue when the sediment filter stages might need attention.



Note the absence of any activity in the pre filter columns for many months. Last time I have a record of any maintenance is end June, the row just cut off in this screenshot. The pressure differential had crept up to 28. I removed the 5 micron, scrubbed the outside of it in the sink & put it back in. Bingo, pressure differential back down to 17 and still there after 4 months. I realize a sediment filter is not that costly, but what the hey, if I can get a few more months out of it.....bonus.

Also note that I multiply the total in cell D53 by 4. This provides an approximate volume of total water throughput based on the manufacturer's specified 1 to 4 product water to waste ratio. This number gives me a better idea of when the carbon block is nearing the end of it's life. The carbon block in my system is supposed to be good for 20,000 gallons. Once I get close to that number, I use a swimming pool water test strip with chlorine indicator on a sample from the output of the carbon filter to make sure it's still doing the job.

Edit: just noticed my comment for cell D53 is in error. The 1 to 4 ratio total only comes into play in cell D54. Need to fix that!