Confusing P04 readings

[dfm34]

After a Dino outbreak I have been cooking my rocks for about 5 weeks in brute trash can. During that time I have been running GFO and testing PO4 with a Hanna ultra low phosphorus checker and my readings have averaged in the. .18 to . 20 range. I did weekly water changes and changed the GFO weekly but could not get below .09.

So I decided to do a bleach and vinegar bath and then a rodi soak. This is were things get confusing.

I had the rocks drying in the sun and was about to add the rocks to a new batch of rodi . For fun I tested the fresh rodi water and to my surprise .20 tested again with different batch of regent .21.

So of course I look at my tsd meter and it reads 1 not great but I don't think it's the cause of the PO4 reading.

Question: do I have a bad test kit??? Is my brute can leaching!?? Do I have a bad rodi filter??

The rocks are siting out dry I want to figure this out before I do anything further with my rocks. Any help is much appreciated.

Dan.

 

[tonizzy22]

If your tds reads 1ppm and your phosphate reads 0.20 ppm I would assume your tests are accurate and your di resin is almost used up. How many di stages on your ro system? How many gallons have you run through it since you last changed the di resin?

 

[Randy Holmes-Farley Verified Community Expert]

You might replace the DI and check that it is 0 ppm TDD, then measure the phosphate in it to see if the kit is working right.

When a DI begins to deplete, phosphate can be among the first things released, and might even be higher than the source water for a while.

 

[dfm34]

I have a 4 stage spectrapure system I have no Idea how many gallons I have run through this since I last changed the filters. It's been about a year since I changed the three filters I don't think I ever in two years the top filter.

I guess I will change all four and start to log my usage so I know the gallons and when to change.

 

[Randy Holmes-Farley Verified Community Expert]

Did it used to read 0 ppm TDS?

 

[dfm34]

Yes randy it did read zero I was under the impression that I did not have to change the filters unless tsd were above 3. I guess I was miss informed.

 

[tonizzy22]

If the di resin hasnt been replaced in a year I think you can get away just by replacing the di resin. That of coarse depends on source water. I go through 2 di resin changes before changing cabon filters. I also backflush the RO membrane regularly. You can also get a 2nd di filter and add it to the output of that filter. You have 1 di stage which never fully gets used up before TDS starts making it through.

 

[dfm34]

Tonizzy22 is there a link that will show me how to add the extra di chamber. Thanks

 

[tonizzy22]

http://www.bulkreefsupply.com/single-deionization-canister.html take the output of your di filter and put it in the new canister and the new canister output to the inline tds meter. I would recommend watching lots of brs youtube videos or ro systems

 

[tonizzy22]

I will get back to you later on the road atm

 

[tonizzy22]

For link on on installation

 

[dfm34]

No worries thanks