PPS Classic Dosing Guide: Perpetual Preservation System for Planted Tanks
Among the major fertilisation methods for planted aquariums, the Perpetual Preservation System stands out for its lean, measured approach. This PPS classic dosing guide planted tank article from Gensou Aquascaping in Singapore explains how PPS Classic works, how to mix the solutions, and how to calibrate daily doses to your specific tank. If you have tried Estimative Index and found it too heavy-handed, or if your plants grow well but algae grows better, PPS Classic offers a disciplined alternative that many aquascapers in Singapore and worldwide swear by.
What Is PPS Classic
PPS Classic was developed by Edward, a planted tank enthusiast, as a method to dose only what plants consume each day, aiming for zero nutrient accumulation. Unlike Estimative Index, which floods the tank with excess nutrients and relies on large weekly water changes to reset, PPS Classic targets precise daily consumption levels. The philosophy is simple: provide just enough macro and micro nutrients each day so nothing builds up and nothing runs out. This lean approach can reduce algae triggers in tanks where excess nutrients contribute to problems, while still ensuring plants receive everything they need.
Solution Recipes
You need two stock solutions. For the macronutrient solution, dissolve 1 tablespoon of potassium nitrate (KNO3), 2 teaspoons of potassium sulphate (K2SO4) and 1 teaspoon of monopotassium phosphate (KH2PO4) in 500 ml of distilled or RO water. For the micronutrient solution, dissolve 1 tablespoon of CSM+B trace mix (or equivalent comprehensive trace powder) in 500 ml of distilled water. Store both solutions in opaque or dark bottles to prevent light degradation. Shake well before each use. These stock solutions last approximately two to three months at room temperature before potency starts to decline.
Daily Dosing Protocol
The standard PPS Classic dose is 1 ml of each stock solution per 40 litres of tank water, dosed daily. For a 200-litre tank, that means 5 ml of macro solution and 5 ml of micro solution each day. Dose macros and micros at the same time; despite older advice suggesting alternating days, research and practical experience show simultaneous dosing works fine. Add the solutions in the morning when lights come on, allowing plants to absorb nutrients during the peak photosynthesis period. Use a graduated syringe or dosing pump for accuracy. Consistency matters more than exact millilitre precision.
Target Nutrient Levels
PPS Classic aims for lean but sufficient nutrient concentrations. Target nitrate (NO3) at 5-10 ppm, phosphate (PO4) at 0.5-1.0 ppm and potassium (K) at 10-15 ppm. Iron should remain detectable on a test kit at around 0.05-0.1 ppm. These are deliberately lower than Estimative Index targets, reflecting the lean philosophy. Test your water weekly during the first month to verify that nutrients neither accumulate nor bottom out. Adjust daily dose volume up or down by 0.5 ml increments based on test results. Once dialled in, testing becomes less frequent as you learn your tank’s consumption patterns.
Water Changes Under PPS Classic
One of the method’s practical advantages is that it does not demand massive weekly water changes. A 20-25% water change every week or two is sufficient, compared to the 50% weekly changes typical of Estimative Index tanks. This is particularly appealing in Singapore, where PUB tap water is chloramine-treated and requires dechlorination. Less water changed means less conditioner used and less disruption to the tank’s biological stability. That said, do not skip water changes entirely. They still remove dissolved organic compounds and replenish minerals that dosing does not address.
Adjustments for Singapore Conditions
Singapore’s tap water is soft at GH 2-4 with low KH. PPS Classic assumes a moderate starting mineral content, so you may need to supplement GH separately using a calcium/magnesium additive if your plants show signs of calcium or magnesium deficiency, such as twisted new growth or interveinal chlorosis. The warm ambient temperature of 27-30 °C accelerates plant metabolism, which may mean you need slightly higher daily doses than the standard recommendation. Start at the base rate and increase by 10-20% if test results show nutrients consistently at zero by evening. Dry fertiliser salts are readily available on Shopee and Lazada for $5-$15 per pack, lasting months of daily dosing.
PPS Classic Versus Other Methods
Compared to Estimative Index, PPS Classic is leaner, uses less fertiliser, requires smaller water changes and suits tanks where algae responds to nutrient excess. Compared to the ADA method, it is simpler and does not require proprietary products. The tradeoff is that PPS Classic demands consistent daily dosing, which some hobbyists find tedious. An automatic dosing pump eliminates this issue and costs $30-$60 for a basic dual-head unit in Singapore. For heavily planted, high-light, high-CO2 tanks, PPS Classic may underfeed demanding species like Ludwigia inclinata ‘Cuba’ or Rotala macrandra. For moderate and low-tech setups, it often hits the sweet spot between healthy growth and algae control. Experiment, test, and adjust to find the balance that works for your specific tank.
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