Phosphate in my RO/DI water

[rort]

I have been fighting a pretty big hair algae problem for a few months now and just cannot win. I have a Phosphate reactor that has been running 24/7 for the last week and I saw a shift to 0 on my test for Phosphate, but in the last few days it has shot back up and I am not seeing any decrease of my hair algae.
I didnt understand where it was coming from so I tested my RO/DI water I make. I am in the process of changing the way I top of my tank as it is a float valve directly into my sump.
- I tested the RO/DI immediately after turning it on to get the higher TDS reading as that is the water that is put into my tank (Float valve pulses on and off so doesnt have time to clear down to 1 on the TDS Reading and usually is up near 35)
- I then tested the water after I left the line open for 30 seconds and got the TDS readings down to 1-2.
After these tests I was shocked to find that the Phosphate readings were pretty damn close to each other. Around 0.25ppm.
Is there something wrong with my RO/DI system or do phosphates normally get through RO/DI's? Is there a way to fix this?

 

[bang guy]

Some phosphate will make it through the RO membrane. None should make it through the DI.

 

[gmann1139]

I just want to make sure I understand this.
You're saying that when you first turn on the RO/DI, you're getting a higher TDS reading, but if you leave the system on, the TDS will drop from 35 down to 2?
Well, the first thing I would do would be to put a bucket or tank inline so that you are running the system less often for more time. That should help right there.
I would also check your filters. As Bang said, any phosphate getting through the Deionizer means the system isn't working properly.

 

[rort]

gmann you got it right. When I let the system run, it drops down to the highest of 2-3.
And if the system isnt working right how would i check it if the TDS is showing me it is correct?

 

[gmann1139]

That 'leakage' may be a sign one or more of your filters is going, specifically the DI component. That's the last polish that removes anything the RO filters missed.

 

[bang guy]

If your TDS is 1 then I suspect the test kit but I've never done the math. Let me run the math and see what your test should read if all of your tds are phosphate.

 

[bang guy]

If I did the math correctly then it is possible for water with a TDS reading of 1 to have 0.25ppm phosphate.

 

[snakeblitz33]

Originally Posted by Bang Guy
http:///forum/post/2917325
If I did the math correctly then it is possible for water with a TDS reading of 1 to have 0.25ppm phosphate.
Wow, that's not good at all!
Then I suggest getting an RO / DI Unit - I have always used DI cartridges with great success.

 

[gmann1139]

Originally Posted by Bang Guy
http:///forum/post/2917325
If I did the math correctly then it is possible for water with a TDS reading of 1 to have 0.25ppm phosphate.
That's assuming that the "1" is all phosphate, correct?
I'm assuming that is mathematically possible, but highly unlikely. Other compounds would be slipping through as well.