Update
Added about 4 to 5 litre jugs of resin. Cylinder now 90% full.
TDS after 15 minutes of running through the DI is flickering between 2 and 1. After always having zero I find this a little unsettling, especially as this is new resin, and the pre-filter was only changed a couple of weeks ago.
TDS from tap is the lowest I've seen it at 253 (could this be down to the hot weather).
TDS in the tank after RO is 48.
TDS in several different clean cups between 1 and 2.
Is it possible that this will sort itself after a bit more water passes through it? If not what can I do?
As always, thanks
If the tap water is 253 and the output after r/o is 48, then there is a problem with your r/o membrane/s. On those figures your r/o is only working at 81% efficiency. Most r/o's work at between 96-99% efficiency unless you have a Merlin that runs at around 90%.
At 253ppm you should be down to around 5ppm after r/o.
Changing prefilters won't make any difference to your tds (ppm) output.
Spruce, thanks for your reply.
Tap water has been as high as the low 400's and the tank would be around 80 with zero still coming out at the pointy end.
Shouldn't the DI be able to cope with 48 down to zero?
Do you think I need a new RO?
Yes it should. But that also depends on how fast you are processing the water through your di vessel. If you are pumping it from an IBC tank through your di onto the van, then the water flow will be too high for your di vessel to cope with. If you were pumping that 48 tds water from your van tank through the di vessel then you shouldn't have a problem as the water is being processed much slower.
Also, having the di vessel on the van does tend to work better as the resin is being shaken around and this will not allow for water paths to form.
There is a cleaner in Middlesbrough that uses 2 di vessels and slowly fills 2 IBC tanks for his requirements with no r/o. He used to use 1 di vessel for a long time and this worked for him as it does other cleaners. His water is similar to ours at 125ppm. But he has to filter the tap water slowly.
We use Tulsion MB115 and it works fine for us. You may have a bad batch of resin (not impossible but unlikely; we always buy this from a known WFP supplier - Purefreedom, Daqua etc.)
Would you be able to identify what the last batch of resin was that you had before? The reason for asking is that Doug from Daqua did say many years ago that some resins work better than others because of the composition of your water. I never understood chemistry at school so Doug's explaination was too complicated for me to understand, but the bottom line was that in some areas Tulsion MB108 would work better than MB115.
