What tds is acceptable for aquarium water?
- Thread starter rapture
- Start date
- Tagged users None
Tds=0
hi rapture, nice to see you over here. :welcome:
As reefing madness stated, 0 is proper. Are you reading something else?
As reefing madness stated, 0 is proper. Are you reading something else?
For RO only which you asked about the treated TDS should be 96-98% less than the tap water was to begin with. For RO/DI the only acceptable TDS is 0. Since RO is only a 90-98% efficient device you really need a final DI stage to get it to 0 TDS which is where you should be for a reef system. You will never see a true 0 TDS with RO only as there are things RO by itself is not particuarly good at removing just as DI by itself os not always good either since there are weakly ionized substances it is not good at so the RO acts as pretreatment for DI.
When you get a reading of 1, it means it's time to check your filters. If you have a spectrapure, their manual is easy to read and it tells you how to test your filters.
russo36
Community Member
Once u start using it on a regular basis... You will be reading 0 right of the start... If is unused for a few days... Then you have to let it run a few seconds
All RO membranes will have elevated TDS on start up, this is due to TDS creep. You will never see 0 TDS from the start since the TDS creep has to be cleared from the treated side of the membrane, flush kits do not do this since they flush only the waste side not the treated side. If you want more bang for your buck install a DI bypass valve and flush the first several ounces to the drain before letting it hit the DI once it is clean.
0 TDS should always be your goal, not sure why anyone would say 30 is OK because it certainly is not. The problem is you have no idea what that TDS is made up of so it could be 30 ppm nitrates, silicates, phosphates, arsenic, who knows what. Since some things are weakly ionized, specifically nitrates, silicates and phosphates, and are not always removed well by RO or DI when it is near exhaustion your goal is 0 TDS and nothing else. That way you know your treated water is good and you have no nagging doubts in the back of your mind. I would never ever use 11 TDS water and certainly not 30. When I first start seeing signs of anything othe rthan 0 TDS after a minute or so the resin gets tossed and new resin or cartridge added.
0 TDS should always be your goal, not sure why anyone would say 30 is OK because it certainly is not. The problem is you have no idea what that TDS is made up of so it could be 30 ppm nitrates, silicates, phosphates, arsenic, who knows what. Since some things are weakly ionized, specifically nitrates, silicates and phosphates, and are not always removed well by RO or DI when it is near exhaustion your goal is 0 TDS and nothing else. That way you know your treated water is good and you have no nagging doubts in the back of your mind. I would never ever use 11 TDS water and certainly not 30. When I first start seeing signs of anything othe rthan 0 TDS after a minute or so the resin gets tossed and new resin or cartridge added.
+1 0 tds is what you are looking for.
Last edited:
Reefer831
2500 Club Member
Are you sure your not reading it before it hits the DI...normal RO will have TDS readings that high...I have seen tons of people with success with just using RO with no problems but I would recommend as close to 0 as you can get...
russo36
Community Member
Absolutely correct.... Once u get something other than that... Is time to chg your filters... If the filters are good or new you need to recalibrate your ro/di filter.
The OP stated "RO unit" which will never have 0 TDS since RO is only 90-98% efficient. RO/DI can and should have 0 TDS and they did state they have 0 TDS from their RO/DI after a bit which is normal once TDS creep clears. Russo I think you mean calibrate their TDS meter but again from the RO only portion of the system you will never have 0 TDS, only from the final RO/DI.
