21 oz Stop Yellow
Product Overview
What pool techs reach for when stubborn mustard and yellow algae resist standard chlorination.
Regal Stop Yellow is formulated to eradicate mustard, green, brown, and pink algae blooms by working synergistically with chlorine shocks. One 21 oz container treats up to 10,000 gallons of pool water, requiring an addition of 2 lbs of shock or 2.5 gallons of liquid chlorine five minutes later. In our experience, it clears blooms effectively regardless of high cyanuric acid levels in both standard and saltwater pools.
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Benefits & What Makes It Different
Rapid Algae Eradication
Clears stubborn yellow, pink, and brown algae within 24 hours when paired with chlorine shock.
CYA Independent Performance
Rids pools of algae effectively regardless of existing cyanuric acid levels or chlorine lock conditions.
21 oz Pre-Measured Treatment
One 21 oz bottle treats up to 10,000 gallons of water for simple, reliable dosing.
Product Details
Disodiumsalt of ethylenediaminetetraacetic acid dihydrate diammonium sulfate 100%
21 oz per 10,000 gallons, followed 5 minutes later by 2 lbs of shock or 2.5 gallons of liquid chlorine
Compatibility
- Compatible with all chlorine and saltwater pool systems
- Do not pre-mix with shock; add shock 5 minutes after adding Stop Yellow directly to pool
- Maintain balanced water: pH 7.2–7.6, total alkalinity 80–120 ppm, cyanuric acid 30–50 ppm
When To Use This
Pro Tip
In hot southern climates where intense UV degrades sanitizer, brush walls thoroughly before adding the 21 oz dose, and verify your water balance sits at pH 7.2–7.6 and total alkalinity 80–120 ppm before adding 2 lbs of shock.
Common Questions & Instructions
How do I add Regal Stop Yellow and chlorine shock together?
Evenly distribute the 21 oz pouch around the pool perimeter. Wait exactly 5 minutes, then add 2 lbs of granular shock or 2.5 gallons of liquid chlorine while maintaining a pH of 7.2–7.6 and free chlorine between 1–3 ppm.
Will Regal Stop Yellow work if my pool has high cyanuric acid?
Yes, Regal Stop Yellow is engineered to deliver results regardless of cyanuric acid levels, making it ideal for treating algae in pools experiencing chlorine stabilizer lock.
Is this yellow algae treatment safe for saltwater pools?
Yes, this formula is fully compatible with both traditional chlorine sanitizing setups and saltwater chlorine generator pools without damaging cell plates.
Delivered today to your DFW neighborhood
Order this item by 2 PM Central on a weekday, and we'll have it on your driveway by evening. Same-day delivery is FREE to every ZIP in our DFW coverage area — no minimum — or it's free with our weekly service plan.
