I currently do not have a lot of time for weekly water changes so want to try the PPS method out? As i understand the "theory" is that you will not require as much water changes as EI? Found the following recipe for PPS-Pro, any of you chem bofs know if this sounds right? http://www.aquaticplantcentral.com/forumapc/pps-analysis-feedback/39491-newbie-guide-pps-pro.html Macro Solution ========= In 1 liter bottle: 59 grams K2SO4 (Potassium Sulfate) 65 grams KNO3 (Potassium Nitrate) 6 grams KH2PO4 (Mono Potassium Phosphate) 41 grams MgSO4 (Magnesium Sulfate) Fill with distilled water and shake well. Let sit overnight. Micro Solution ========= In 1 liter bottle: 80 grams of CSM+B or equivalent trace element mix Fill with distilled water and shake well. Let sit overnight. Dose 1 ml of each solution per ten gallons of tank size. Dose prior to lights turning on.
Thanks for the links. I'm still studying them. My first question is the high Potassium and sulfate content of the fert mix, as well as the absence of Calcium. I'll be back when I'm ready checking this out further.
The lack of calcium could be a problem in areas with soft water. The Ca:Mg ratio is normally 4:1 (m/m) so I would mix 28 g of MgCl2 together with 131 g CaCl2. These chloride salts may be harder to find than the sulfates... CaNO3 could also work but would need to be prepared in a different bottle to sulfates as CaSO4 is poorly soluble (as is calcium phosphate). If you are not doing regular water changes I would advise against adding any phosphates at all. Phosphates accumulate very fast in a closed system, especially in the substrate. In the substrate it is perfectly fine because this is where the plants take it up in any case. I don't see much need for K2SO4 either. Plants should get more than enough S from fishfood.
Macro Solution ========= In 1 liter bottle: 59 grams K[sub]2[/sub]SO[sub]4[/sub] adds 26mg K[sup]+[/sup]/ml to the mixture. 65 grams KNO[sub]3[/sub] adds 36mg NO[sub]3[/sub][sup]-[/sup]/ml, as well as 25mg K[sup]+[/sup]/ml to the mixture. 6 grams KH[sub]2[/sub]PO[sub]4[/sub] adds 4mg PO[sub]4[/sub][sup]3-[/sup]/ml, as well as 2mg K[sup]+[/sup]/ml to the mixture. 41 grams MgSO[sub]4[/sub] adds 4mg Mg[sup]2+[/sup]/ml to the mixture. The mix contains a total of 53mg K[sup]+[/sup]/ml, and 51mg SO[sub]4[/sub][sup]2-[/sup]/ml. Obviously, Calcium is not including in this mix because of the sulfate content which would react with the Calcium to form almost insoluble gypsum (CaSO[sub]4[/sub]). Adding 1mL of mix to 10 gallon (≈ 40L) introduces: 1.4 ppm K[sup]+[/sup] (total) 0.95 ppm NO[sub]3[/sub][sup]-[/sup] 0.11 ppm PO[sub]4[/sub][sup]3-[/sup], and 0.13 ppm Mg[sup]2+[/sup]. I'm a bit unhappy about the choice of chemicals and I also agree with Tyrone's comments. Finally, This is NOT a new system. Fertilisation regimes based on periodic test results were - as far as I can recall - already introduced in the early 80's.
Re: PPS-Pro fertilization - Can anyone comment please got the following quote? Can anyone comment please Got the following quote from Kimix chemicals & Labortory suppliers in Epping Cape town, Potassium Nitrate AR - 500g @ R62(ex) Magnesium Sulphate anhydrous CP - 500g @ R69(ex) Potassium Sulphate AR – 500g @ 136(ex) Potassium DI hdy ortho phosp ar - 500g @ R79(ex) DI Potassium hdy ortho phosp ar – 500g @ R178(ex) Then is the below correct, DI Potassium Hydrogen Orthophosphate is also known as POTASSIUM PHOSPHATE Dibasic Potassium Dihydrogen Orthophosphate is also known as POTASSIUM PHOSPHATE Monobasic. So I assume will need to use “Potassium DI hdy ortho phosp ar” ?
Prices look good and you have the names right. Yes, use the Potassium DI hdy ortho phosp. It has a pKa of 7.2 so it won't mess with your pH. The moment you get BGA, stop adding the P and up the N.