RODI not doing enough

[Royalreef22]

So I am ready to fill my tank but my RODI unit isn’t taking out all the phosphates. Still at 0.36 ppm with a Hanna checker. TDS is 241 before RODI 5 after RO and 0 after DI. Can I add another RO membrane to an aquatic life RODI?!? Please advise I want to get my tank filled!

 

[lapin]

Yes.

 

[Royalreef22]

Yes.

How would that work with waste water is my question

 

[lmm1967]

consider a booster pump as well

 

[lapin]

It will not do anything to your waste water. The waste water comes out before the DI part of the unit

 

[Royalreef22]

consider a booster pump as well

U mean for higher pressure?

 

[92Miata]

Mix up 5 gallons of salt water and then test it. The Hanna meter isn't going to give your proper results on RODI

 

[Royalreef22]

It will not do anything to your waste water. The waste water comes out before the DI part of the unit

I want to add an RO not DI. RO seems more effective at removing phosphates. If I have it go through the first RO then the second RO then it would take forever the make water and waste a ton of water because I have two waste water drains. One for each RO and I don't want that

 

[Royalreef22]

Mix up 5 gallons of salt water and then test it. The Hanna meter isn't going to give your proper results on RODI

On BRS website it says it's ok for freshwater to what's the difference?

 

[lapin]

My error DI RO i didnt read your 1st post correctly

 

[lmm1967]

U mean for higher pressure?

yes

higher pressure (to a point of course) will lower the waste output and help the system to be overall more efficient

I'd also get a second test to confirm your hannah is accurate

 

[lapin]

You could add another RO cartridge after the first. However, its going to produce waste water so you would have less good output water.
Their maybe an issue with pressure to the second unit making it less effective also.
Most people that have water issues end up using 3 DI resin beds.

 

[92Miata]

On BRS website it says it's ok for freshwater to what's the difference?

Which one are you using? Both the ULR ones (which are the good ones) are marine only. The LR and HR ones are either - but you're testing way below the range where they are useful.


The issue is that RODI isn't just "fresh water" - its absolutely stripped water - and the tests aren't designed for that.


Phosphate is weakly charged - but DI should strip it out.

 

[Royalreef22]

Which one are you using? Both the ULR ones (which are the good ones) are marine only. The LR and HR ones are either - but you're testing way below the range where they are useful.


The issue is that RODI isn't just "fresh water" - its absolutely stripped water - and the tests aren't designed for that.


Phosphate is weakly charged - but DI should strip it out.

I have the HI 713

Ok I will mix some saltwater and try it again

 

[gray808]

I'd also get a second test to confirm your hannah is accurate

I see this, or a similar sentiment all the time on this site.

But I never see anyone report back "Yep, my Hanna was wrong" or "Nope, the Hanna was right".

I'd like to know how often people get a Hanna checker (for pretty much anything), that is actually giving incorrect readings when administered correctly.

And how off is it? If the actual sample is, say, 9 ppb, but the checker is reading 11 ppb, I'm going to be way less worried about it than if it's supposed to be 9 ppb, and is reading 0 or 1782 ppb.

--Gray

 

[92Miata]

I see this, or a similar sentiment all the time on this site.

But I never see anyone report back "Yep, my Hanna was wrong" or "Nope, the Hanna was right".

I'd like to know how often people get a Hanna checker (for pretty much anything), that is actually giving incorrect readings when administered correctly.

And how off is it? If the actual sample is, say, 9 ppb, but the checker is reading 11 ppb, I'm going to be way less worried about it than if it's supposed to be 9 ppb, and is reading 0 or 1782 ppb.

--Gray

My Hanna alk checker is off by about .5 dkh at 8 dkH, and about .3 dKH with the reference solutions(5dkh) It's about a month old. My ULR Phosphate checker is off by about .05 with the reference solutions. I have no way to validate it a low range.

There are plenty of threads about this stuff.


The Phosphate checkers are known to read high with RODI - its just not what theyre designed for.

 

[lmm1967]

I believe most test kit problems are user error and some people have more problems with some types of testing methods.

 

[Billldg]

So I am ready to fill my tank but my RODI unit isn’t taking out all the phosphates. Still at 0.36 ppm with a Hanna checker. TDS is 241 before RODI 5 after RO and 0 after DI. Can I add another RO membrane to an aquatic life RODI?!? Please advise I want to get my tank filled!

Hanna Checkers have a margin of error. I have them and use them as well. You are fine to use the water. You could upgrade to a 7 stage to remove it further. I am upgrading to a 7 stage, not because I need to, I am doing it because its gives me the peace of mind knowing that I am doing all I can to make sure the water is pure. Most of use have a P04 above .07-.10.