The short answer: 2Hr Aquarist APT 3 is the better liquid fertilizer if you run a tank without CO2 or want one bottle that works in almost any planted setup. MasterLine All In One is the better choice if you want the lowest cost per month and a formula tuned to your exact tank: Lean for aquasoil (with or without CO2), Golden for inert substrate and demanding plants with CO2, Boost for fast Dutch-style growth with CO2. For a 100 litre tank, MasterLine costs about €2.50 to €3.20 a month, APT 3 about €5 to €5.80. Below: a side-by-side table, how to match the formula to your substrate and CO2, real cost per month, and the mistakes that turn fertilizer into algae food.
Contents
- What is an all-in-one aquarium fertilizer?
- APT 3 vs MasterLine All In One: side-by-side comparison
- Do I need CO2 to use an all-in-one fertilizer?
- Which MasterLine All In One should I choose?
- What about APT e and the Estimative Index?
- How much does each fertilizer cost per month?
- Which fertilizer should you choose?
- Frequently asked questions
What is an all-in-one aquarium fertilizer?
An all-in-one liquid fertilizer puts the macronutrients (nitrogen, phosphorus, potassium, magnesium) and the micronutrients (iron, manganese, zinc, boron, copper, molybdenum) into a single bottle. Instead of dosing three to five separate products, you dose one, once a day. That is why both APT 3 and MasterLine All In One are among the best-selling fertilizers in our store: they remove the guesswork without giving up on complete nutrition.
The difference between brands is not "complete vs incomplete". Both are complete. The difference is the ratio of nutrients, the concentration, and the type of tank each one is designed for. Pick the wrong ratio for your tank and the surplus nutrients feed algae instead of plants.
APT 3 vs MasterLine All In One: side-by-side comparison
| 2Hr Aquarist APT 3 | MasterLine All In One (Golden / Lean / Boost) | |
|---|---|---|
| Made in | Singapore (The 2Hr Aquarist, Dennis Wong) | Romania (MasterLine) |
| Works without CO2 | Yes, faster results with CO2 | Lean: yes, on aquasoil. Golden and Boost: no, they need CO2 |
| Daily dose | 3 ml per 100 L (or 5 ml per 100 L, 4 times a week) | 1 ml per 30 L (about 3.3 ml per 100 L) |
| Formula approach | One balanced, slightly nitrate-limiting formula for most planted tanks | Separate formulas by tank type: Golden, Lean, Boost (plus nitrate-free Red) |
| Shrimp safe | Yes, at the label dose | Yes, at the label dose |
| Sizes | 200, 300 (with pump), 500, 1000 ml | 200, 500, 1000, 5000 ml |
| Cost per month, 100 L tank | about €4.90 to €5.70 | about €2.50 to €3.20 |
| Best for | Low-tech and high-tech tanks, beginners, "one bottle for everything" | Aquascapers who want a formula matched to their substrate, plants and CO2 |
One complete bottle for almost any planted tank. The 300 ml pack includes a calibrated 1 ml pump.
Do I need CO2 to use an all-in-one fertilizer?
It depends on the formula, and this is where most people pick the wrong bottle.
APT 3 works in both CO2 and non-CO2 tanks. In a low-tech tank, plants grow slower and use less, but the balanced ratio keeps nutrients from piling up. With CO2, the same bottle simply delivers faster, denser growth.
MasterLine All In One Lean also works without CO2, as long as the tank runs on aquasoil. Its low nitrogen dose is small enough for slower low-tech growth, and the plants take the rest from the substrate.
MasterLine Golden and Boost are formulated for CO2-injected tanks. Without CO2, plants cannot use their higher dose, and the leftover nitrate and phosphate become available to algae. If you do not inject CO2, choose APT 3 or Lean, or read our guide Do you really need CO2 in your aquarium? first.
Liquid carbon (such as MasterLine Carbo) helps low-tech tanks, but it is not a full replacement for injected CO2 when you are choosing a CO2-only fertilizer.
Which MasterLine All In One should I choose?
MasterLine splits its all-in-one range by tank type. All three below use the same dose (1 ml per 30 L daily); what changes is how much nitrogen each one delivers. Calculated from the label analysis, one daily dose adds roughly:
- All In One Lean: about 0.6 ppm NO3 per day. For tanks on active aquasoil, where roots already have a nutrient reserve, with or without CO2. Slower, compact growth with stronger colour.
- All In One Golden: about 1.2 ppm NO3 per day. For inert substrates (sand, gravel) and demanding plants that struggle under standard dosing. Thicker leaves and stems.
- All In One Boost: about 1.5 ppm NO3 per day, the strongest in the range. For Dutch-style and fast stem-plant tanks (Rotala, Ludwigia, Alternanthera) with strong light.
The fourth option, All In One Red, contains no nitrate at all. It is meant for heavily stocked tanks where fish waste already supplies nitrogen, and for pushing red plants to their deepest colour.
Complete nutrition for demanding plants on inert substrate. Stronger roots, thicker growth.
Lower nitrogen so plants feed from the roots. Compact growth, richer colour, less trimming.
What about APT e and the Estimative Index?
APT e is the 2Hr Aquarist answer for advanced, heavily planted CO2 tanks. It is built on the Estimative Index (EI) method developed by Tom Barr: you supply nutrients in mild excess, so nutrients are never the limiting factor, and you reset the build-up with a large weekly water change (typically around 50%). The dose is 2 ml per 100 L daily.
EI is not a beginner method. It works brilliantly with strong light, stable CO2 and disciplined water changes. In a low-tech tank, a fish-heavy tank or a new aquasoil setup under three months old, the excess is more likely to feed algae. In those cases APT 3 (or APT 1 for fish-heavy and brand-new soil tanks) is the safer choice.
Concentrated EI fertilizer for high-tech Dutch-style tanks. 300 ml with calibrated pump.
How much does each fertilizer cost per month?
Bottle price says little on its own, because the doses differ. Here is the real cost of the label dose in a 100 litre tank over 30 days, at our current prices:
| Fertilizer | Used per month | 500 ml bottle | 1000 ml bottle |
|---|---|---|---|
| APT 3 | 90 ml | €5.74 | €4.94 |
| APT e | 60 ml | €4.38 (300 ml bottle) | |
| MasterLine Golden, Lean or Boost | 100 ml | €3.15 | €2.54 |
For a 60 litre tank, multiply by 0.6; for 200 litres, double it. If you run a large tank on MasterLine, the 5 litre bottle brings the cost down further.
Which fertilizer should you choose?
- No CO2, sand or gravel: APT 3.
- No CO2, aquasoil: MasterLine All In One Lean (cheaper per month) or APT 3.
- New aquasoil tank (under 3 months) or lots of fish, few plants: APT 1 or MasterLine All In One Red, both without added nitrate.
- CO2 + aquasoil: MasterLine All In One Lean.
- CO2 + sand or gravel, demanding plants: MasterLine All In One Golden.
- CO2 + strong light + lots of fast stem plants: MasterLine All In One Boost, or APT e if you follow EI with large weekly water changes.
- You want one bottle that keeps working if you change your setup later: APT 3.
Whatever you choose, dose at the same time every day. An automatic doser makes that effortless; see Aquarium dosing pump: is it worth it?
Three mistakes that turn fertilizer into algae food
1. Using Golden or Boost without CO2. The plants cannot use the full dose and the surplus feeds algae.
2. Fixing every yellow leaf by adding more fertilizer. Pale, holed older leaves often point to potassium, while pale new growth points to iron. Diagnose before you double the dose. Our guide on potassium deficiency shows what to look for.
3. Running activated carbon or UV while fertilizing. MasterLine specifically warns against it, because both strip trace elements out of the water.
Give your plants the right formula
APT 3 for any tank, MasterLine All In One matched to your setup. Both in stock and shipped across Bulgaria and Europe.
Shop APT 3 →Not sure which one fits your tank? Message us a photo and we will tell you.
Frequently asked questions
Is APT 3 better than MasterLine All In One?
Neither is better in every tank. APT 3 is more versatile and works without CO2. MasterLine is cheaper per month and offers formulas matched to specific setups. Without CO2, only Lean (on aquasoil) fits; Golden and Boost need CO2.
Can I mix APT 3 and MasterLine fertilizers?
It is not recommended to dose two complete all-in-one fertilizers together, because you double the nutrients without knowing the ratio. If you switch brands, stop one and start the other, then watch your plants for two to three weeks.
How long does a bottle of fertilizer last?
In a 100 litre tank, a 500 ml bottle of APT 3 lasts about 5.5 months and a 500 ml bottle of MasterLine All In One about 5 months at the daily label dose. The 2Hr Aquarist bottle sizes are rated for about 3 months in the tank size printed on the label.
Are all-in-one fertilizers safe for shrimp?
Yes. Both APT 3 and MasterLine All In One are formulated with shrimp-safe copper levels when dosed as directed. Never overdose in a shrimp tank, and add a new fertilizer gradually.
When should I dose liquid fertilizer?
Dose daily, ideally at the start of the light period or after a water change, with the filter running so the fertilizer spreads evenly. Keep liquid carbon on a separate schedule a few hours apart.
Is an all-in-one fertilizer enough, or do I need separate macros and micros?
For most planted tanks, an all-in-one is enough. Separate macro and micro fertilizers only pay off in demanding high-tech tanks where you want to fine-tune each nutrient individually based on tests and plant response.