Test kit that works for RO/DI water

[RealReefHobbyist]

Are there any confirmed test kits that can test low levels of phosphate in RO/DI water?

I want to soak some dry rock and watch the phosphate levels as it soaks in RO/DI water. I figured there’s no sense wasting salt if it can be avoided.

 

[Joe31415]

I'd think any test kit would work, IIRC, a bunch of rock in not a lot of water should make the phosphate spike more than high enough to read. However, I don't know if using a marine test kit in RODI will work. You might want to pick up one that works with freshwater.
However, another option, is to use old water from water changes. Let the rocks sit in a bucket of old tank water and replace it once or twice a week.

 

[Randy Holmes-Farley Verified Community Expert]

The Hanna HI713 claims to work in fresh water.

Low Range Phosphate Colorimeter - Checker® HC

The HI713 Checker®HC (Handheld Colorimeter) provides a simple, accurate and cost effective way to measure phosphate.

www.hannainst.com

 

[RealReefHobbyist]

The Hanna HI713 claims to work in fresh water.

Low Range Phosphate Colorimeter - Checker® HC

The HI713 Checker®HC (Handheld Colorimeter) provides a simple, accurate and cost effective way to measure phosphate.

www.hannainst.com

Great thanks. I’ll check it out.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, the release of phosphate will be different in RO/DI compared to seawater, and is also pH dependent. I expect much less comes off into fresh water for various chemical detail reasons relating to the forms of phosphate present in each.

Thus, you can monitor it, but I would not draw too strong of a conclusion from RO/DI about what exactly would happen in seawater.

 

[RealReefHobbyist]

FWIW, the release of phosphate will be different in RO/DI compared to seawater, and is also pH dependent. I expect much less comes off into fresh water for various chemical detail reasons relating to the forms of phosphate present in each.

Thus, you can monitor it, but I would not draw too strong of a conclusion from RO/DI about what exactly would happen in seawater.

Thank you for that, so helpful! Would the opposite be true then? Would high salinity water release the phosphates faster?

 

[Randy Holmes-Farley Verified Community Expert]

Thank you for that, so helpful! Would the opposite be true then? Would high salinity water release the phosphates faster?

Not noticeably, but acid (such as vinegar or diluted muriatic acid) will strip it faster. No need for salt water then.

 

[RealReefHobbyist]

Not noticeably, but acid (such as vinegar or diluted muriatic acid) will strip it faster. No need for salt water then.

I’d like to do the muriatic acid, but I’m hoping to do something quite replicable. Many people would be nervous to work with a strong acid.

I haven’t heard of the vinegar method. Do you have some info on that you could share?

 

[RealReefHobbyist]

Not noticeably, but acid (such as vinegar or diluted muriatic acid) will strip it faster. No need for salt water then.

I’ve heard a few days in a bleach bath also strips out phosphate. Would that be better?

 

[Randy Holmes-Farley Verified Community Expert]

I’ve heard a few days in a bleach bath also strips out phosphate. Would that be better?

No, that’s for organic removal. Acid is for phosphate removal.

 

[RealReefHobbyist]

No, that’s for organic removal. Acid is for phosphate removal.

Got it! Is there a ratio of vinegar to water? Heated or room temp water? How long would you allow it to soak?

Thank you Randy! Appreciate you and all you do for the hobby!

 

[Randy Holmes-Farley Verified Community Expert]

Room temp. You might dilute one part vinegar in say 5 parts ro/di, and let it soak until the bubbling stops.

 

[RealReefHobbyist]

Perfect. I’m going to go for that. Thanks as always.

 

[dadnjesse]

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