Question about RODI water and Water hardness!

[bfazio1030]

Hello I am new here. I made 5 gallons of RODI water and tested the hardness with a tds meter. It read 22. After adding my salt mix it then jumped up to 420. Does adding salt increase the hardness of the RODI water? Also do I have to dechlorinate my RODI water? Im new to this as you can see! Any help would be greatly appreciated! Thanks guys!

 

[lazycouch]

Hello I am new here. I made 5 gallons of RODI water and tested the hardness with a tds meter. It read 22. After adding my salt mix it then jumped up to 420. Does adding salt increase the hardness of the RODI water? Also do I have to dechlorinate my RODI water? Im new to this as you can see! Any help would be greatly appreciated! Thanks guys!

yes tds measures purity of the water so salt will definitely read that high. you want to get a reading of 0, 22 is still pretty high and would be almost pointless to make rodi and still have to dechlorinate. your rodi system might need a new filter!

 

[MaxxuM]

Hello I am new here. I made 5 gallons of RODI water and tested the hardness with a tds meter. It read 22. After adding my salt mix it then jumped up to 420. Does adding salt increase the hardness of the RODI water? Also do I have to dechlorinate my RODI water? Im new to this as you can see! Any help would be greatly appreciated! Thanks guys!

Did you run your RODI unit for an hour or two before using it? Could still have carbon or preservatives in it.

TDS measures desolved solids in your water so 22 means there's still something in there after RODI. 22 isn't bad for your aquarium so you don't have to dechlorinate, but this could mean your filters are failing or just don't have a great rejection rate. Test your tap water and compare the before and after filtration.

 

[bfazio1030]

yes tds measures purity of the water so salt will definitely read that high. you want to get a reading of 0, 22 is still pretty high and would be almost pointless to make rodi and still have to dechlorinate. your rodi system might need a new filter!

Thanks for the reply. I thought it was high as well. Its a brand new RO BUDDIE +DI. Maybe i need to run it more?

 

[neiltus]

Are you on a well? CO2? I am wondering what would make a new ro unit throw 22. I echo you don't want that.

Tell us your source, and each stage or your entire RO unit. U have a carbon block. Is this water that has been through a softer?

 

[bfazio1030]

Did you run your RODI unit for an hour or two before using it? Could still have carbon or preservatives in it.

TDS measures desolved solids in your water so 22 means there's still something in there after RODI. 22 isn't bad for your aquarium so you don't have to dechlorinate, but this could mean your filters are failing or just don't have a great rejection rate. Test your tap water and compare the before and after filtration.

Will try running the unit for 2 hours. My tap water registered at about 450-470.

 

[neiltus]

Will try running the unit for 2 hours. My tap water registered at about 450-470.

city tap? or well tap? This sounds like well through a softner in which case if your starting that high, your little ro buddy is going to need (if it can) a lot more carbon and di changes than it's worth.

Since you did not disclose, and your just calling it tap, if it's well with Co2-that eats carbon quick, and that ends up putting a larger load on DI.

If you on a well, or there is high co2, your going to need a few real carbon blocks before that unit.

 

[old salt reefer]

And I thought my city water was bad at 120TDS out of the tap.

 

[bfazio1030]

city tap? or well tap? This sounds like well through a softner in which case if your starting that high, your little ro buddy is going to need (if it can) a lot more carbon and di changes than it's worth.

Since you did not disclose, and your just calling it tap, if it's well with Co2-that eats carbon quick, and that ends up putting a larger load on DI.

If you on a well, or there is high co2, your going to need a few real carbon blocks before that unit.

It is city tap water. Not sure if there is softener in it?

 

[neiltus]

It is city tap water. Not sure if there is softener in it?

do you have a water softener in the garage or somewhere else in your dwelling?

it's prob full of minerals and Co2 at that level of input. Couple 1m pre filters and at least 2 1m carbon blocks, prob 2 full size DI unit's too that will need refreshing every 3-6 months at that level of input.

Sorry. I start with 13ppm city where I am at with chloramine. Your prob on non fluoride city that is just spring water from one of the escarpments. Good water to drink. But those minerals your starting with are higher PPM than Perrier.

 

[neiltus]

go online and access your city or muni water report. That 400ppm will be explained there, if it's not, you have some really bad galvanized pipe or something dumping crap.

 

[MaxxuM]

Will try running the unit for 2 hours. My tap water registered at about 450-470.

Is this a new RODI unit? If it is then it requires at least 2 hours of running to clear it of residue and preservatives. If its old then you need to replace the pre-filter, sediment, and carbon media. DI resin is "Use Once" only so you don't need to run it until your main filter is done "clearing its throat". Never connect your DI resin until the unit has been run for 2 hours because it will just be wasted.

450-470 is a little above US average. Mine is 630 (not great). That just means my filter media will be used up faster. You could have 1,000 TDS and a good RODI unit should bring it to 0, but the media will be exhausted much faster. Cheap filter media will have a lower "rejection rate" and need to be changed sooner.

Many fish stores only use RO water and reagualarly hit in the 10-30 range, so like I said, 22 isn't "harmful". It just isn't optimal.

 

[Sisterlimonpot]

Hello I am new here. I made 5 gallons of RODI water and tested the hardness with a tds meter. It read 22. After adding my salt mix it then jumped up to 420. Does adding salt increase the hardness of the RODI water? Also do I have to dechlorinate my RODI water? Im new to this as you can see! Any help would be greatly appreciated! Thanks guys!

A lot to clarify here, first off a tds meter doesn't test for hardness it detects desolved solids by measuring the conductivity of the water. TDS can be comprised of much more than the elements that contribute to hard water.

As mentioned a few times by other posters, 22 at the end of the DI stage is unacceptable, that's even a bit high for coming out of the membrane. 0 is what you want to see post DI.

The one thing that stood out on your post is that you detected chlorine after water has went through your RODI unit. Which is a clear indication that the RO membrane is no good. The number one killer of RO membranes is chlorine. Hence the carbon block prefilter(s). The RO unit relies a lot on the carbon block to remove all traces of chlorine before entering the membrane.

At the very least your problem begins at the prefilter stage, and may also lead to needing a new membrane as well.

Get yourself a set of new prefilters and test again... if after, the tds is still high out of the membrane I would also replace that.

 

[Sisterlimonpot]

so like I said, 22 isn't "harmful". It just isn't optimal.

I disagree with this. Unless you know what the 22 is, then I wouldn't trust it. If it were magnesium, then all is good. But it can also be copper or some other harmful element.. and then all is bad!

Contributing a blanketed statement like that is dangerous.

 

[LegendaryCG]

Yep test rodi before adding salt. 22 isn’t typically awful but you should be able to reach zero, you may need to add extra stages or a booster pump to do so.

I live literally in a town named Silica and I have a 4 stage RO and a 2 stage DI and can get to zero with it.

 

[neiltus]

I would be changing out all my filters at 20+, granted back in 80s I ran a much crappier ro and was prob above that.

but OP.....if that 22 ends up in the tank, it could trash coral or maybe just make you change gfo every 2 weeks. If I was fish only I might trust it.....

 

[CK00020]

I have well water it’s like 48 tds after softening then it still makes my sediment filter orange, so I added another, but after my membrane I still only get 1 after creep, then it goes to di which takes care of the rest. I wouldn’t use 22 tds water

 

[DSEKULA]

go online and access your city or muni water report. That 400ppm will be explained there, if it's not, you have some really bad galvanized pipe or something dumping crap.

This isn't necessarily true, while it's nice to check i prepare these reports for a living. The only information that has to be included are contaminates that are tested and present in the source. For instance co2 isn't something normally tested so it could be present and just not tested. Another example is if you test for copper the mcl is 1.3 mg/L most labs will test a threshold of .1 mg/L if the threshold isn't met it won't be shown on the report. This doesn't mean it's a true 0.00 as <0.09 is considered safe to drink but you probably don't want that much copper in a tank. Anyway, just an explanation of how these reports work.

 

[MaxxuM]

I disagree with this. Unless you know what the 22 is, then I wouldn't trust it. If it were magnesium, then all is good. But it can also be copper or some other harmful element.. and then all is bad!

Contributing a blanketed statement like that is dangerous.

Well if you're in Flint Michigan a few years ago, it might be bad. It's highly unlikely that anything in that range would be harmful to most tanks. In the last forty years and seven different cities I've used water in that range with no issues, but you're right. Everyone's mileage will vary.

 

[DSEKULA]

I'm also confused how your testing hardness with a tds meter, hardness as caco3? As mn? Total hardness or are you just confusing tds with hardness?
Hardness as caco3 will blow through all those filters and only get removed by the di portion, if you are truly facing hardness you need a cation bed to remove.

My well water comes in at about 350ppm tds with about 200mg/L as CaCO3 here's the system I built, you can get to 0 it just takes a little more work. If you have more information on your source water post it and I'll try to help.