Sodium Nitrate and Trisodium Phosphate Precipitating?

[joshbd]

I'm moving away from NeoPhos and NeoNitro to DIY using sodium nitrate and trisodium phosphate, both of which are supposedly food grade. I'm currently mixing a ratio of 50 grams : 1L of sodium nitrate, and separately 2 grams : 1L of trisodium phospate. These amounts appear to completely dissolve (and stay dissolved) at these ratios in warm RODI water. However, I was hoping to mix the two solutions 50/50 to save on a dosing head (appreciating this will dilute each 50%), but when I do I'm getting a smallish amount of whitish precipitation on the bottom of the container, which I didn't think should happen.

Any idea what this is, and if it's safe to dose? Is it a potential impurity? Can I just decant the clear liquid off the top and use that? Thanks!

 

[chipmunkofdoom2]

I do the same. I start with a concentrated Na3PO4 solution (7.5g/L) that tends to have some white precipitate, but I dilute it before mixing with the NaNO3 solution. Once I dilute and mix it in with the NaNO3 solution (52g/L), I don't have any precipitate.

 

[Randy Holmes-Farley Verified Community Expert]

There may be a small amount of an ion such as calcium or magnesium in the sodium nitrate, and it will preciptitate with the phosphate. I'd just ignore it.

 

[joshbd]

Excellent, thanks so much!

 

[Huey_Gnr]

I'm moving away from NeoPhos and NeoNitro to DIY using sodium nitrate and trisodium phosphate, both of which are supposedly food grade. I'm currently mixing a ratio of 50 grams : 1L of sodium nitrate, and separately 2 grams : 1L of trisodium phospate. These amounts appear to completely dissolve (and stay dissolved) at these ratios in warm RODI water. However, I was hoping to mix the two solutions 50/50 to save on a dosing head (appreciating this will dilute each 50%), but when I do I'm getting a smallish amount of whitish precipitation on the bottom of the container, which I didn't think should happen.

Any idea what this is, and if it's safe to dose? Is it a potential impurity? Can I just decant the clear liquid off the top and use that? Thanks!

I was wanting to do the same thing: out of curiosity what is your tank's water volume and are you seeing the appropriate consistency is relation to nitrate and phosphate levels as you were dosing each separately?

I also dose NaNO3 and Na3PO4 separately at the moment.

 

[joshbd]

The tank is Redsea Reefer 350 G2, so 90G total volume. In terms of target levels, I try to keep Nitrates at 5-10ppm and Phosphates .05-.1ppm. Right now, I'm adding 5ml daily of the premixed solution (25G Sodium Nitrate and 2G Trisodium Phophate in 1L RODI). So, according to the planted tank calculator, this should a about .22ppm Nitrate and .02ppm Phosphate. Will continue testing every couple of days and adjust the solution until I get something that more closely matches my relative uptake to keep me in the target range (likely this will mean adding more sodium nitrate, but we'll see).

At the end of the day, I'm far more concerned with keeping phosphates in the desired range, as long as nitrates stay above 0 and below 20ppm.

 

[Huey_Gnr]

The tank is Redsea Reefer 350 G2, so 90G total volume. In terms of target levels, I try to keep Nitrates at 5-10ppm and Phosphates .05-.1ppm. Right now, I'm adding 5ml daily of the premixed solution (25G Sodium Nitrate and 2G Trisodium Phophate in 1L RODI). So, according to the planted tank calculator, this should a about .22ppm Nitrate and .02ppm Phosphate. Will continue testing every couple of days and adjust the solution until I get something that more closely matches my relative uptake to keep me in the target range (likely this will mean adding more sodium nitrate, but we'll see).

At the end of the day, I'm far more concerned with keeping phosphates in the desired range, as long as nitrates stay above 0 and below 20ppm.

Awesome, thanks!

 

[House_of_Coral]

I'm moving away from NeoPhos and NeoNitro to DIY using sodium nitrate and trisodium phosphate, both of which are supposedly food grade. I'm currently mixing a ratio of 50 grams : 1L of sodium nitrate, and separately 2 grams : 1L of trisodium phospate. These amounts appear to completely dissolve (and stay dissolved) at these ratios in warm RODI water. However, I was hoping to mix the two solutions 50/50 to save on a dosing head (appreciating this will dilute each 50%), but when I do I'm getting a smallish amount of whitish precipitation on the bottom of the container, which I didn't think should happen.

Any idea what this is, and if it's safe to dose? Is it a potential impurity? Can I just decant the clear liquid off the top and use that? Thanks!

What products did you use for each?