Every commercial feeding protocol rests on assumptions it never states, because in the climate it was written for they cost nothing. This article takes one published protocol, Advanced Nutrients’ 8th Gen Elite Protocol, and tests six of those assumptions against a Thai flowering room at 31 °C and 85% RH. The six are how long a batch tank keeps, how long stock concentrate keeps, how often tanks need sanitising, whether your room appears on the VPD table, whether high EC is a free choice, and how warm the reservoir runs. Thailand meets one related assumption for free: mixing water at 24 °C or warmer. The rest fail to some degree, and the lessons on batch life, VPD and EC apply whatever brand you feed. Every adjustment below is our inference from how the system works, not manufacturer guidance. We looked for an Advanced Nutrients hot-climate protocol and found none.
1. Disclosure and scope
Disclosure: we (AZ Grow / AZ Growshop) are an authorized distributor of Advanced Nutrients in Thailand.
Scope: this compares a published protocol with a tropical climate. When we say a number does not fit a Thai room, we mean the assumption behind it fails. We do not mean you should feed something else.
The line is registered with the Thai Department of Agriculture. Check the registration number on the label; status as of 4 September 2026. A DOA registration is permission to trade a product. It is not a published composition.
Sources, accessed 14 October 2026. The 8th Gen feeding page (Advanced Nutrients 8th Gen Protocols | Commercial) hosts the eight feed-chart variants and two guides: “Guide to Create a Stock Concentrate” (https://www.advancednutrients.com/commercial-sop/stock-concentrate-sop.pdf) and “Guide on Determining Feed Strength”, the EZ-switch SOP (https://www.advancednutrients.com/commercial-sop/ez-switch-sop.pdf). The batch tank procedures SOP and the crop steering cheat sheet are also manufacturer documents, but we could not find them at a public link. Check the current versions before relying on figures quoted from them.
The eight chart variants differ by units (imperial or metric), EC strategy (high or regular) and concentrate form (liquid or dry). None of them differs by climate, and we found no tropical adjustment guidance.
2. Assumption one: a batch tank keeps for 24 to 48 hours
What the batch tank SOP says:
- Use a batch mix within 24–48 hours. Holding it longer is flagged as a risk. (Stock concentrate has its own separate 7-day limit, covered in section 3.)
- Keep water at 65–75 °F (18–24 °C) for oxygen availability.
- Monitor and record batch-tank EC and pH rather than trusting the recipe.
- Fill to about 80% of final volume and add nutrients one part at a time, mixing 2–5 minutes between parts. Top up last, so the final concentration comes out right.
- For nutrients in suspension, agitate within 15 minutes before irrigating, and avoid pumps that introduce air.
What a Thai store room does: an unconditioned room in Buriram or Bangkok stays above 24 °C most of the year, day and night. A batch tank stored there sits at that same temperature.
Why 48 hours depends on temperature: microbes grow faster as water warms. The 48-hour limit really means “use it before the biology in the tank changes the solution”, and at 30 °C that happens sooner than at 20 °C. Treating “48 hours” as a fixed allowance means using a temperate allowance in a tropical tank. The SOP’s own troubleshooting note points the same way. It says water quality, poor storage or third-party products may cause pH swings, and advises sanitising before refilling. In a temperate document “poor storage” means a dirty tank. In Thailand it also means a hot one.
3. Assumption two: stock concentrate keeps a week (and mixing water is at least 24 °C)
What the stock concentrate guide says:
- Mix in RO water at a minimum of 75 °F (24 °C) for solution stability, and store at 65–75 °F.
- Weigh powder at 1 lb or 2 lb per final gallon. The powder adds roughly 5–10% to the volume.
- Mix until fully dissolved, and check the tank floor for undissolved material.
- Avoid placing tanks directly on concrete floors or anywhere the temperature fluctuates.
- Use stock concentrate made from dry powders within 7 days.
- Label each tank with the mix, the validated EC and the date.
The one assumption Thailand meets for free: the 24 °C minimum exists so the powder dissolves, and tropical water is already that warm without heating. In a temperate winter, cold RO water dissolves powder poorly. A Thai facility avoids that problem entirely.
The assumption Thailand breaks: the 7-day stock life follows the same temperature logic as batch life, so expect it to be shorter in the heat. The concrete rule assumes concrete is the cold surface in the room. In Thailand it may be the coolest surface available, so the rule as written points the wrong way. Its real aim, avoiding temperature swings, still holds.
The validation step is what protects you. Add 10 mL of concentrate to 990 g of RO water and read the EC against target; ±0.1 is acceptable. It takes two minutes. When you can’t be sure how long stock keeps, a validation reading beats the date on the tank.
4. Assumption three: sanitising intervals
What the SOPs say:
- Sanitise stock tanks with bleach or an oxidising product.
- Mineral-based nutrient tanks: every 1–3 months.
- Carbon-based inputs (plant extracts, humates, kelp): every 2–4 weeks.
- Empty and rinse tanks between batches. Batch tanks should be used up completely and at least rinsed between mixes.
- Each facility should set its own deep-cleaning frequency by monitoring buildup.
The manufacturer already cleans carbon-based tanks about two to three times as often as mineral ones, because carbon gives microbes something to eat. Biofilm grows faster with more food and with more heat, so a hot tank pushes the same way as a carbon-rich one. If your additives include plant extracts, humates, kelp or carbohydrates, start from the carbon-based interval.
The line that matters is the last one: set the frequency by your facility’s conditions. The 1–3 month figure is a temperate default, and the SOP itself tells you to override it.
5. Assumption four: you can find your room on the VPD table
For VPD basics, see topic 1046 (Climate Control/VPD). This section covers only where the protocol’s table runs out.
The crop steering cheat sheet gives ideal VPD of 0.8–1.1 kPa in vegetative growth and 1.0–1.5 kPa in flowering, at sea level. It sets leaf temperature targets of 72–76 °F under HPS and 76–80 °F under LED. Its humidity columns run from 75% down to 40% in 5-point steps, and its temperature rows run from 60 to 85 °F. The warmest row is the one a tropical grower is closest to:
| 85 °F (29.4 °C) | 75% | 70% | 65% | 60% | 55% | 50% | 45% | 40% |
|---|---|---|---|---|---|---|---|---|
| kPa | 1.0283 | 1.2340 | 1.4397 | 1.6453 | 1.8510 | 2.0567 | 2.2623 | 2.4680 |
We checked the 75% cell with the Tetens equation and got about 1.03 kPa, which matches the sheet.
A Thai monsoon flowering room falls off this table in both directions: hotter than 29.4 °C and more humid than 75% RH. The most humid cell on the sheet, 1.03 kPa, is already at the bottom of the flowering range, and a Thai room is more humid still.
Here is the calculation the table can’t do for you. At 31 °C and 85% RH, saturation vapour pressure is about 4.49 kPa (Tetens), so air VPD ≈ 4.49 × (1 − 0.85) ≈ 0.67 kPa. That is air VPD, not leaf-to-air VPD, and it is our arithmetic, not a manufacturer figure.
0.67 kPa is below the stated vegetative minimum and well below the flowering range. The cheat sheet itself states what follows: “If VPD is too small, peak growth rates are not achieved and problems like root rot or mold can become an issue.” For a Thai grower that is the most useful sentence in the whole reference, and it does not appear on the feed chart. A high-EC feed in a room at 0.67 kPa goes to a plant that is not moving water.
6. Assumption five: high EC or regular EC is a free choice
The feeding page gives two EC versions of the same recipe as separate files, not as a range.
Transpiration decides which one a room can run. A high-EC feed puts more nutrients into each litre of water. That works when the crop moves a lot of water: high light, tight irrigation control and reliable runoff. At 0.67 kPa the crop doesn’t move that much water, so a high-EC feed tends to build up in the medium. The medium’s EC rises while the feed EC reads exactly as the chart says.
That is why runoff EC tells you more here than feed EC. The gap between the two is the only direct evidence of buildup. Two points support logging it. Feed-chart EC figures generally assume RO water as the base, so you have to account for your source water’s EC separately; check the notes on your chart variant. And the EZ-switch SOP says to change feed EC in steps of 10–20% when switching brands. Both points say the same thing: the EC number on the chart is not a measurement of your root zone.
7. Assumption six: the reservoir stays at 18–24 °C
The batch tank SOP asks for 65–75 °F (18–24 °C) for oxygen availability. For nutrients in suspension, it asks for light agitation within 15 minutes before irrigating, and says to avoid pumps that add air, such as air stones, to prevent contamination. That creates a real conflict: the roots need oxygen in the water, but contamination control wants no air in the mix. A commercial layout handles this with two different tanks. A grower with a single reservoir is being asked to do both in one.
In Thailand, the temperature requirement is the harder one. Warmer water holds less dissolved oxygen, while warmer roots need more of it, so the shortfall grows from both sides. A reservoir left at room temperature in a 31 °C room sits about 7 °C above the protocol’s 24 °C maximum, and more on hot afternoons. The protocol states 18–24 °C as a requirement and offers no alternative. A room that cannot hold that range is outside what the document covers, not at its edge.
8. What survives, and what does not
| Protocol assumption | In a Thai room |
|---|---|
| Mixing water ≥ 24 °C | Met for free by tropical water, no heating needed [inferred] |
| Batch mix used within 24–48 h | Fails as a fixed allowance: microbes act faster in warm water [inferred] |
| Stock within 7 days; avoid concrete | Same failure, so validate by EC, not date. Concrete may be the coolest surface; the aim of avoiding temperature swings still holds [inferred] |
| Sanitise mineral tanks every 1–3 months | A temperate default; the SOP’s “set frequency by your facility’s conditions” is the rule to follow [verified] |
| Room findable on the VPD table; 1.0–1.5 kPa in flower | Impossible: the table stops at 29.4 °C and 75% RH, and 31 °C / 85% RH gives ≈ 0.67 kPa air VPD [verified table limits; calculated VPD] |
| High EC is a free choice | It is not: transpiration is the limit [inferred] |
| Reservoir 18–24 °C | Needs cooling equipment; the protocol offers no alternative [verified as an absence] |
9. If you are switching in a Thai room
What you gain: the base nutrients and the procedures work in any climate. Solubility, mixing order, validation arithmetic, pH targets for each medium and injector order all hold anywhere. None of the chemistry fails at 31 °C, and that is most of what you are buying. What fails is every assumption about time and temperature, plus the table that would place your room. That is a narrower problem than “this protocol does not work here”.
What you give up: a chart you can follow without thinking. In a temperate room the protocol’s conditions come for free. Here you have to measure them, and two of them (reservoir temperature and room VPD) need equipment to fix. A Thai facility needs more instruments to run this protocol than a Canadian one does. That costs labour and meters, not product.
Where the risk is: time and temperature, in that order. Batch and stock tanks both last less time here than the documents assume, and neither failure is obvious. You see pH drift, EC drift, and a crop underperforming for reasons that look like nutrition. The second risk is picking the high-EC chart because it sounds more ambitious, in a room whose VPD shows the crop is not moving water.
What to do first in this climate:
- Before changing nutrients, put one thermometer in the store room and one in the reservoir.
- Log temperature and humidity at canopy height so you calculate VPD rather than look it up.
- Start on the regular-EC chart. Moving up later on runoff evidence is safer than finding out you were building up salt.
- Mix smaller batches more often, and validate every stock tank by EC before use.
- From day one, log feed EC, runoff EC and source-water EC every day.
Fix one thing before the fertiliser. If your reservoir sits near room temperature, that affects this crop more than any change of nutrient line. Switching nutrient systems while the root zone is about 7 °C above the protocol’s range (more on hot afternoons) is optimising the wrong variable.
10. Measurements worth posting
Nobody has posted these from a Thai room yet, and each one is cheap to take:
- Batch tank pH and EC at mixing, at 24 h and at 48 h, in an unconditioned store room
- Stock validation EC before each use, logged
- Feed EC and runoff EC daily, per room, with source-water EC subtracted
- Temperature and humidity at canopy height, so VPD is calculated rather than read off a table that doesn’t go that high
- Reservoir temperature, which almost nobody measures
Any one of these, posted for a single crop, would help growers here more than the entire launch package for the line.
Related reading: topic 1046 (Climate Control/VPD).
This article is technical horticultural information for readers operating legally in their jurisdiction. Cannabis cultivation is regulated differently in every country. In Thailand, cannabis flower is a controlled herb under the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis) B.E. 2568. It may be dispensed only against a PT 33 prescription from an authorised practitioner, it may not be sold or advertised online, and cultivation and sale require licensing. The Cannabis Control Act is still a draft (Cabinet-approved 22 September 2026, now before the House). Nothing here is legal advice.