Phosphates in my tank - what gives?

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neilanh

Sliced Bread
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Dec 25, 2006
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So as my tank is still new, I'm starting to see some small signs of hair algae. Expected, to say the least, and much less so far than I anticipated. But, I wanted to do some digging.

I tested my tank just prior to this week's 33% PWC. Phosphates were 0.5ppm. Hmm, higher than expect. So, I tested my RO/DI water straight out of the tap. 0.5ppm. Well, that explains the tank. So then I tested my source water, before and after the first few stages of the filter but before the membrane, 2.0ppm. So, the RO Membrane is getting most of it out, but what to do about the last little bit?

I am running a phosban reactor on the tank, and measured it's output at 0.0ppm, so it's doing it's job, but yet I still have phosphate in the tank.

Sparky and Ziggy and I were talking, and had discussed running a 2d Phosban reactor on my stored water prior to PWC may be a good idea. But, I don't store water for top off, so I'd still be adding in phosphates through my current top off process.

Then, I started thinking - what about running a reactor of sorts in-line with my RO/DI unit. The flow rate would surely be slow enough for it to be probably overly effective, and I haven't yet come up with any downsides to this.

Or, if my RO Membrane is removing 1.5ppm, why not run 2 inline.

Any thoughts, or anyone else dealt with this same situation?
 
Can you fill up one of the canisters with a phosphate removing media? How many DIs to you have? If you have you could run it in one of those.
Or, could you take off the phosphate reactor and run it on your top-off until phosphates are 0?
 
Yes. DI resins catch all charged molecules.
 
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IMO one of the chief places that phosphates come from is the food we feed them. Flakes and frozen are notorius for adding phosphates to the tank. Your water issues might be some of the reason but check out your food.
 
AGreed melosu, but I'm trying to clear the source... 1 step at a time

I did change the DI resin, and there is some improvement. I doubt the quality of my hobby grade test kits means much, but there is a bit of a difference now after swapping out for fresh DI resin.

I'll go with this for a bit and see where I end up. Thanks for all the help!
 
That`s fine. When you are ready for some food tips let me know and I`ll post them. I hope you get it under control.
 
The ro would take most of it out (depending on the quality of the membrane), the di should be finishing the job. You shouldn't have any PO4 readings or at least very negligible from the unit as you already know. What tds are you running by chance after ro and after di stages?
 
Ive never checked the TDS at the output of the membrane, but at the output of the DI it's been running 0-2. With the new resin, it appears to be solid at 0.
 
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