EI vs PPS-Pro Dosing Comparison Guide: Which Method When
Two dosing philosophies have ruled high-tech planted tanks for over a decade, and choosing between them sets the rhythm of your tank maintenance for years. EI vs PPS Pro is the classic crossroads — the abundance-and-reset Estimative Index against the precision-balance Perpetual Preservation System. This comparison from Gensou Aquascaping at 5 Everton Park lays out target concentrations, weekly time investment, and the tank profiles where each method shines.
The Two Underlying Bets
EI bets that nutrients are cheap and water changes solve everything. Dose excess, change 50 per cent weekly, plants take what they want, residue flushes. PPS-Pro bets that you can hold ideal water column concentrations indefinitely with daily small doses and zero water changes (in theory) — uptake equals input, parameters stay flat. EI is forgiving but sloppy; PPS-Pro is precise but punishes neglect.
Target Concentrations Side by Side
EI weekly accumulated targets: NO3 20-30 ppm, PO4 3-6 ppm, K 30 ppm, Fe 0.5 ppm. PPS-Pro daily steady-state: NO3 5-10 ppm, PO4 0.1-1 ppm, K 5-10 ppm, Fe 0.1 ppm. The difference reflects philosophy: EI accumulates a ceiling then resets, PPS-Pro maintains a floor at all times. Test kits matter more under PPS-Pro because you cannot rely on the weekly water change to mask drift.
Water Change Burden
EI demands a 50 per cent water change every 7 days. For a 200-litre tank in an HDB flat that means dechlorinating 100 litres, GH-boosting it, and pumping it in — about 45 minutes weekly. PPS-Pro reduces water changes to 30-50 per cent monthly or even quarterly, which sounds great until you realise it requires near-perfect dosing precision and active testing every fortnight to catch drift. A submersible pump for water changes is essential either way.
Daily Time and Equipment
EI splits doses across three days weekly — about 5 minutes total. PPS-Pro doses daily, every single day. That 60 seconds of daily attention sounds trivial until you travel — a fortnight away starves a PPS-Pro tank. A dosing pump is functionally optional for EI but mandatory for PPS-Pro unless you have a willing house-sitter.
Algae Risk Profile
EI runs nutrient excess all week. With stable CO2 (30 ppm, 1.2+ pH drop) and balanced light (60-100 µmol PAR), this is fine — plants outcompete algae easily. With unstable CO2 or excess light, EI’s nutrient surplus accelerates algae blooms. PPS-Pro runs leaner, so the same lighting/CO2 imbalance still triggers algae but slower and at smaller scale. PPS-Pro is more forgiving of equipment failures, less forgiving of dosing failures.
Plant Response Differences
EI tanks grow fast — Rotala rotundifolia can need weekly trimming on EI versus fortnightly on PPS-Pro. Inter-nodes are looser under EI; PPS-Pro produces tighter, more compact growth that aquascapers prefer for competition tanks. Red plants typically colour better under PPS-Pro because lower phosphate frees iron for uptake. EI is the production-line method; PPS-Pro is the boutique method.
Singapore Tap Water Implications
PUB water’s GH 2-4 baseline matters more for PPS-Pro because the long intervals between water changes mean Ca and Mg deficits accumulate faster. PPS-Pro keepers in Singapore must dose Ca/Mg into the water column daily as part of the macro mix. EI keepers solve this at the weekly water change with GH booster. The test kits range stocks GH/KH reagents that are non-negotiable for both methods.
Cost Comparison
Dry-salt EI for a 200-litre tank: SGD 10-15/year. Dry-salt PPS-Pro for the same tank: SGD 6-10/year (lower doses). Equipment cost diverges sharply: EI runs fine on manual dosing with a syringe (SGD 5), PPS-Pro practically requires a dosing pump (SGD 80-200). Over five years total cost evens out around SGD 250 either way.
Which Method to Pick
Pick EI if you have a fast-growing stem-heavy or carpet-heavy scape, you don’t mind weekly water changes, you travel rarely, and you are still learning to read plant deficiencies. Pick PPS-Pro if you have a matured tank with slow growers, prefer monthly water changes, own a dosing pump, and are comfortable with weekly testing. Pick lean dosing (a third path) if neither fits — most modern aquascapers have moved that direction.
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