phosphate dosing

[rog2961]

I was going to try phosphate dosing as I believe i have reached the limit with nitrate dosing. Looking at monosodium phosphate or trisodium phosphate. Problem is I dont know how much to use. For kno3 dosing I used 100g kno3 in 500ml water, calculator says 10ml of this would raise 1000l by 1.12ppm. I'd like to get my phosphate around .1 or so.

 

[Randy Holmes-Farley Verified Community Expert]

Which product? Both are fine if adequately pure.

 

[rog2961]

trisodium phosphate, seems like its easier to get

 

[Randy Holmes-Farley Verified Community Expert]

Do you have a scale for weighing, or go by spoonfuls?

Na3PO4 is 58% phosphate by weight.

Adding 1 gram (580 mg phosphate) into 1000 L tank volume boosts phosphate by 580/1000 = 0.58 mg/L (too much).

 

[rog2961]

I use a scale. So I would need about 250mg to raise it .014?

 

[Randy Holmes-Farley Verified Community Expert]

No. 0.014/0.58 = 24 mg.