---
title: "Mustard Algae Killer — $236K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/patio-lawn-garden/mustard-algae-killer"
last_updated: "2026-08-11T07:43:56.643Z"
locale: en
meta:
description: "Niche score 59/100 · $236K/yr market. A failed launch gate (market size, growth, or returns) keeps it on the watch list. Data updated Jul 2026."
"og:description": "Niche score 59/100 · $236K/yr market. A failed launch gate (market size, growth, or returns) keeps it on the watch list. Data updated Jul 2026."
"og:title": "Mustard Algae Killer — $236K/yr Amazon US Niche (2026) - Flapen"
---
# **mustard algae killer**
**Worth a look**
Shows searches that convert (18.0% search→purchase), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.
Market size 44Growth 97Conversion 99Competition 0Returns 97Price range 89Avg price 95Brand share 0Review moat 66Quality gap 58
**Conversion**
**Incredible****18.0%**
search→purchase rate — share of searches ending in a sale
**Growth**
**Incredible****+184.6%**
90-day search growth — must beat 0% to launch
**Returns**
**Incredible****0.5%**
return rate — above 5% kills the launch gate
**Avg price**
**Incredible****$39.15**
avg listing price — sweet spot $15–$100
**Price range**
**Great****$9.52–$85.03**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Review moat**
**Good****846.2**
avg incumbent reviews — the moat a new listing must climb
**Quality gap**
**Good****4.4★**
avg incumbent rating — lower means beatable quality
**Market size**
**Okay****$236K**
$236K/yr · 34K searches
**Competition**
**Bad****100%**
top-5 click share — a locked-up shelf
**Brand share**
**Bad****100%**
top-5 brand share — brand-locked demand
**Signals**[** Trending**](https://flapen.com/research/niches?market=us&signal=trending "Search growth > 100% (90d)")
According to Flapen's Amazon United States niche tracking, mustard algae killer is a $236K/yr Amazon United States market (34K searches/yr). The top 5 brands hold 100% of demand. Demand peaks in Apr–May–Jun–Jul–Aug. Verdict: Worth a look — 59/100.
Data updated Jul 24, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **mustard algae killer market data**
- **Units sold / yr**
- **6K–8K**
- avg 1,250–1,500/product
- **Revenue / yr**
- **$235K–$313K**
- units × avg price
- **Conversion rate**
- **18.0%**
- **Avg BSR**
- **#79**
- **Page quality**
- **0%**
- **Prime**
- **100%**
- **Sponsored**
- **40%**
- **Out of stock**
- **0.0%**
- **Avg brand age**
- **92 months**
- **Avg seller age**
- **158 days**
## **Competition & brand share**
The top 5 products capture 100% of clicks — a locked-up shelf that new listings rarely crack.
**Brands**
**2 **▼falling
**Sellers**
**36**
**Top-5 brand share**
**100%**
Top 20: 100%
**Top-5 click share**
**100%**
Top 20: 100%
**Open market**
**0%**
- United Chemical97% - APPLIED BIOCHEMISTS3%
## **Demand & seasonality**
Weekly Amazon search volume, last 102 weeks — +184.6% search growth over the last 90 days.
2K1KSpike '25Spike '26 seasonDecMarJunAugNovMarMay
Peak months: Apr, May, Jun, Jul, Aug · busiest ÷ quietest = 11.9×
[**Open Trend **](https://flapen.com/research/us/patio-lawn-garden/mustard-algae-killer/trend)
## **Top mustard algae killer search terms**
- **yellow treat algaecide**19K/yr+188.8%19.0% conv. - **yellow treat**12K/yr+119.5%17.6% conv. - **yellow treat algaecide for swimming pool**3K/yr+520.6%16.5% conv. [**All search terms **](https://flapen.com/research/us/patio-lawn-garden/mustard-algae-killer/search-terms)
## **Top mustard algae killer products on Amazon**
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
0%15%$35K30%$71K45%$106K60%$141K1001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 5 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**United Chemicals Yellow Treat Mustard Algaecide for Swimming Pool Super Strength Algae Killer for Mustard & Yellow Algae in Saltwater & Chlorine Above & Inground Pool Treatment | YT2-2LB**United Chemical**$24.51**4.3★2,032 rev](https://www.amazon.com/dp/B001P41TLO) [2**United Chemicals YellowTreat Mustard Algaecide for Swimming Pool Super Strength Algae Killer for Mustard & Yellow Algae in Saltwater & Chlorine Above & Inground Pool Treatment | YT2-2LB-C2**United Chemical**$41.71**4.5★1,195 rev](https://www.amazon.com/dp/B00JCEEKR4) [3**United Chemical Yellow Treat Mustard Algaecide 5 oz**United Chemical**$9.52**4.3★408 rev](https://www.amazon.com/dp/B00OOAPNF4) [4**United Chemicals Yellow Treat 2 lb - YT-C12 - 4 PACK**United Chemical**$85.03**4.6★157 rev](https://www.amazon.com/dp/B074B4MJ7F) [5**Applied Biochemists Pool 408622A Yellowtrine Swimming Pool Algaecide Cleanser 3 lbs**APPLIED BIOCHEMISTS**$34.99**4.3★439 rev](https://www.amazon.com/dp/B00PM8Q96O)
### **Newest**
by launch date
[**United Chemicals Yellow Treat 2 lb - YT-C12 - 4 PACK**United Chemical**$85.03**157 rev8y ago](https://www.amazon.com/dp/B074B4MJ7F) [**United Chemical Yellow Treat Mustard Algaecide 5 oz**United Chemical**$9.52**408 rev11y ago](https://www.amazon.com/dp/B00OOAPNF4) [**United Chemicals YellowTreat Mustard Algaecide for Swimming Pool Super Strength Algae Killer for Mustard & Yellow Algae in Saltwater & Chlorine Above & Inground Pool Treatment | YT2-2LB-C2**United Chemical**$41.71**1,195 rev12y ago](https://www.amazon.com/dp/B00JCEEKR4) [**Applied Biochemists Pool 408622A Yellowtrine Swimming Pool Algaecide Cleanser 3 lbs**APPLIED BIOCHEMISTS**$34.99**439 rev15y ago](https://www.amazon.com/dp/B00PM8Q96O) [**United Chemicals Yellow Treat Mustard Algaecide for Swimming Pool Super Strength Algae Killer for Mustard & Yellow Algae in Saltwater & Chlorine Above & Inground Pool Treatment | YT2-2LB**United Chemical**$24.51**2,032 rev16y ago](https://www.amazon.com/dp/B001P41TLO)
### **Trending**
90-day click momentum
[**Applied Biochemists Pool 408622A Yellowtrine Swimming Pool Algaecide Cleanser 3 lbs**APPLIED BIOCHEMISTS**$34.99**4.3★**▲ 13%**](https://www.amazon.com/dp/B00PM8Q96O) [**United Chemicals Yellow Treat Mustard Algaecide for Swimming Pool Super Strength Algae Killer for Mustard & Yellow Algae in Saltwater & Chlorine Above & Inground Pool Treatment | YT2-2LB**United Chemical**$24.51**4.3★**— 8%**](https://www.amazon.com/dp/B001P41TLO) [**United Chemical Yellow Treat Mustard Algaecide 5 oz**United Chemical**$9.52**4.3★**— 5%**](https://www.amazon.com/dp/B00OOAPNF4) [**United Chemicals Yellow Treat 2 lb - YT-C12 - 4 PACK**United Chemical**$85.03**4.6★**— 1%**](https://www.amazon.com/dp/B074B4MJ7F) [**United Chemicals YellowTreat Mustard Algaecide for Swimming Pool Super Strength Algae Killer for Mustard & Yellow Algae in Saltwater & Chlorine Above & Inground Pool Treatment | YT2-2LB-C2**United Chemical**$41.71**4.5★**▼ 19%**](https://www.amazon.com/dp/B00JCEEKR4)
## **What buyers say about mustard algae killer**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Value For Money**22%
*“easy ordering and good pricing”*
**Quality-Overall**15%
*“Excellent product”*
**Instructions/User Manual/Troubleshooting**15%
*“Easy to follow instructions”*
**Water Resistance**8%
*“Water is crystal clear just a day after application”*
**Ease Of Cleaning**7%
*“This algaecide works really well for keeping my pool clean and algae-free”*
**Ease Of Use**6%
*“Easy to use”*
**Strength**5%
*“Effective”*
**Eco Friendliness**5%
*“The pool is high maintenance due to the environment”*
**Plant Growth**5%
*“it seems to help with algae blooms”*
**Brightness/Shine/Glow**5%
*“Perfect for keeping your pool a sparkling blue all season long”*
### **What buyers complain about **
**Functionality-Overall**42%
*“Didnt work”*
**Contamination**25%
*“I was having a problem with mustard algae appearing on the walls of my in-ground plaster pool with a DE filtration system”*
**Plant Growth**8%
*“I did end up having to buy 4 total bottles to get the mustard algae bloom beaten back”*
**Maintenance And Repair**8%
*“This wasn't a permanent fix”*
**Advertised Vs Actual Product**8%
*“Deceptive advertisement”*
**Value For Money**8%
*“I did find a product at Home Depot that does about the same for a cheaper price”*
### **Top return reasons **
**Advertised Vs Actual Product**34%
**Functionality-Overall**21%
**Leak-Proof**14%
**Suitable For Outdoor**5%
**Value For Money**5%
**Product Condition**4%
**Contamination**3%
**Size-Overall**3%
**Instructions/User Manual/Troubleshooting**2%
**Water Resistance**2%
## **Common questions**
- **Is mustard algae killer profitable to sell on Amazon United States?**
- The niche generates $236K/yr across 5 tracked products. 90-day search growth is +184.6%. Flapen's verdict: Worth a look (59/100).
- **How competitive is the mustard algae killer niche?**
- 2 brands and 36 sellers compete. The top 5 products take 100% of clicks and top 5 brands hold 100% of demand.
- **What do buyers complain about in mustard algae killer?**
- Top complaints mined from reviews: Functionality-Overall, Contamination, Plant Growth. The return rate is 0.5%.
- **When does demand for mustard algae killer peak?**
- Demand peaks in Apr–May–Jun–Jul–Aug; the busiest month runs 11.9× the quietest.
- **What does it cost to enter the mustard algae killer niche?**
- Listings span $9.52–$85.03; the average listing price is $39.15 (sweet spot $15–$100). The average incumbent carries 846 reviews — the moat a new listing must climb.
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