Do I need to dose phyto if I don't have clams or filter-feeders?

Only if you have a copepod-dependent species like a mandarin dragonet or scooter blenny, or a chaeto refugium that benefits from pod populations. Otherwise it's optional.

Will phyto cloud my display tank?

Slightly, for 30–60 minutes after dosing. That's normal. Dose into a high-flow sump area; the cloud disperses by the next photoperiod.

What's the difference between live and bottled phyto?

Live phyto is actively reproducing cells. Most bottled products are live at the start but die off over 1–3 months on the shelf. DIY culture is fully live and continuously refreshed.

Calculator

Phytoplankton Dose Calculator (Live Phyto)

Name: Phytoplankton Dose Calculator (Live Phyto)
Author: reefcalcs

Live phytoplankton feeds filter-feeders (clams, sponges), seeds copepod populations, and supports refugium chaeto growth indirectly. Concentrated bottles (Reef Nutrition PhytoFeast) dose at lower volumes; generic live nanno is more dilute. This calculator gives you per-dose mL and bottle-life estimates.

JavaScript is disabled in your browser, so the interactive calculator below won't run. The math, formula, and worked example are all written out further down this page under “How this is calculated.” Enable JS (or open this page in another browser) to use the live calculator.

Whether you compute by hand or in the calculator, the same caveat applies: verify against your test kit and the linked primary source before dosing. reefcalcs is reference information, not veterinary or engineering advice.

Phytoplankton dose

Tank volume (US gal)

Product

Doses per week

Per dose

3mL

Per week

6mL

16 oz bottle lasts

552days

Concentrated phyto (PhytoFeast) doses at 1 mL per 25 gal; generic live nanno at 1 mL per 10 gal. Refrigerate after opening; shake before dosing.

How this is calculated

Per-dose volume by product:
  Reef Nutrition PhytoFeast (concentrated): 1 mL / 25 gal
  Brightwell PhytoChrom:                    1 mL / 20 gal
  Generic live nanno (bottled):             1 mL / 10 gal
  DIY home culture:                         1 mL / 10 gal

mL per week = mL per dose × doses per week
Bottle life = 473 mL / (mL per week) × 7  (16 oz bottle)

Refrigerate phyto immediately on receipt and after every use. Shake before dosing — live algae settles. Bottles past 3 months from opening have most cells dead; the green colour stays but the nutritional value drops.

If you dose more than 3×/week, DIY nanno culture pays for itself in 2–3 months. A 2L culture vessel + nutrients + air pump costs ~$50 and produces 2L of dense phyto per week indefinitely.

FAQ

Do I need to dose phyto if I don't have clams or filter-feeders?: Only if you have a copepod-dependent species like a mandarin dragonet or scooter blenny, or a chaeto refugium that benefits from pod populations. Otherwise it's optional.
Will phyto cloud my display tank?: Slightly, for 30–60 minutes after dosing. That's normal. Dose into a high-flow sump area; the cloud disperses by the next photoperiod.
What's the difference between live and bottled phyto?: Live phyto is actively reproducing cells. Most bottled products are live at the start but die off over 1–3 months on the shelf. DIY culture is fully live and continuously refreshed.

Share / embed this calculator

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<iframe
  src="https://reefcalcs.com/embed/phyto-dose/"
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></iframe>

Sources & references

01
Reef Nutrition — PhytoFeast product page
https://www.reefnutrition.com/products/phytofeast/
02
BRS — phyto dosing guide
https://www.bulkreefsupply.com/content/post/phytoplankton-the-pros-and-cons-of-dosing-phyto-and-pods

Last reviewed 2026-05-25