Reverse Osmosis Filter Troubleshooting

[steelhealr]

HI...I have an RO/DI filter that is getting up there. I tested the water with a TDS meter tonite. Here are the readings after each stage:

1) tap water, 90
2) 1st stage (the three large canisters), 108
3) RO filter, 52
4) DI, 8

SH

 

[steelhealr]

No takers? LOL. I'll post what I think is the implication of those numbers later. SH

 

[N1z]

If im thinking along the same lines, looks like u need a new carbon and sediment filter and prehaps the other one i dunno wots you have got running in it. As for the membrane looks like it might need replacing very soon also.

I hate to brag but guess what my tap water is 240 and after my small 3 stage i get 6ppm!

 

[SkiFletch]

Well, assuming those numbers are all AFTER the components listed instead of before, it indicates that your RO membrane either needs a good flushing or is finally comprimised. I'd first flush it for 10-20 mins and then see if the TDS post-RO comes down to under 10ppm, prefferably in the 3-5 range or less.

I would also replace at least my sediment pre-filter as the higher TDS there indicates it is packed and leeching rust or other sediment back into the line.

Lastly, after flushing/replacing the membrane and replacing the pre-filters that are clearly nastified, I'd double check the DI performance. It might be time to replace the resin, but if for example the RO TDS comes in at 3-5 and the DI TDS comes in at 0-1, its probably still ok.

 

[steelhealr]

I think you are pretty much on the money Ski. The TDS goes up after going thru the prefilters. They are probably clogged with debris after all this time. Then, the RO memberane only drops the TDS by 50%. I'll flush it and recheck, but, I think it may be at the end of it's lifespan. After the RO, it goes from 52 to 8 thru the DI resin...that's a huge drop and probably means the resin is still good.

Overall, you all know that an RO membrane is not cheap...I think on the order of $60-70. I think the whole unit needs to be replaced if you ask me. I'll give the membran a good flush tonite and recheck all numbers. It's a good exercise in thinking since most of us, I would guess, don't go thru the motions of checking how our filters are functioning...until algae hits. SH

 

[SkiFletch]

It's a good exercise in thinking since most of us, I would guess, don't go thru the motions of checking how our filters are functioning...until algae hits. SH

Yeah, dont remind me

 

[steelhealr]

Interesting followup. Check out the photo of my filter below:

I disconnected the sixth stage of my filter (D) since it is present for flavor only (crushed coconut shell) and actually can add TDS to the water. Now, if you look at 'L' connector on the DI stage , letter C, you can see that if you rotate the cylinder, the outflow can change position. Well, the outflow connector was pointed up...the DI resin was on the bottom of the cylinder, so, water could pass over the resin and out resulting in inadequate filtration. I rotated the outflow down, tilted the filter so the resin piled up over the outflow, and BEHOLD:

0 TDS

SH