Anyone use Triple Super Phosphate?

[Disaronno]

Normally I'd use mono potassium phosphate but the price has risen considerably since last purchased so I'm looking for alternatives.

Let's use Bonide TSP 0-45-0 as an example. SDS states 100% calcium dihydrogenphosphate (CAS# 7758-23-8), molecular formula CaH4P2O8.

The calcium itself does not concern me as I normally add calcium sulfate anyway. However are there any other drawbacks from using TSP? Also how to calculate the dosage?

 

[_Maq_]

Calcium phosphates are poorly soluble. This fertilizer is meant to stay in the soil and dissolve slowly. In the tank, it will work in a similar fashion. It's a long-term source of phosphorus, not readily available like potassium phosphate.
If the price is your concern, check for price of phosphoric acid.

 

[Disaronno]

Ah haven't thought about the solubility... 2g/100mL hmm... yea might have some problems if I tried making a macro solution instead of dry dosing to the tank.

Tried using openai to do the calculations, the results were atrocious. One of the results said over 900 grams to raise P by 1ppm for 60 gallons 😱

 

[dw1305]

Hi all,

instead of dry dosing to the tank.

It probably wouldn't be my phosphate (PO4---) source of choice (it is made by pouring phosphoric acid (H3PO4) onto mined rock phosphate) but I'd just dry dose it.

Personally I'd go with potassium dihydrogen phosphate (KH2PO4) if I wanted a separate phosphate source. You aren't going to need a vast amount of PO4---, so you aren't adding an excess of potassium (K).

There are always likely to be problems with calcium (Ca++) and phosphate (PO4---) ions in concentrated solutions.



cheers Darrel