Leaves, Acorns, and Algae: September's Debris Triple Threat
September 17, 2026 | Pool Care Tips
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Minnesota yards are full of oaks and maples, and September sends all of it your way at once. Leaves drop, acorns fall, and warm afternoons still give algae a chance to bloom. Three problems, one pool. Here is how to handle each one before it turns into a bigger job.
1 The Leaf Problem: Why Wet Leaves Are Worse Than They Look
A dry leaf on the water is easy. A wet leaf that sinks and sits is not. Leaves that stay on the bottom overnight can leave a stain, especially on plaster and light vinyl liners. They also start to break down fast, and that breakdown feeds algae and pulls down your chlorine level.
Skim daily during heavy drop weeks. A leaf net over the pool at night saves you a lot of morning work.
If daily skimming is not in the cards, the Dolphin Skimmi 300 can take that job off your plate. It is a solar-powered surface skimmer that charges up during the day, then works through the night collecting leaves, bugs, and other floating debris. You wake up to a clean surface without lifting a net.
2 The Acorn Ambush: Small Nuts, Big Trouble
Acorns are small, hard, and everywhere near oak trees. They sink fast and end up in the skimmer basket, the pump basket, and sometimes the impeller. A pump basket packed with acorns cuts water flow and can make your pump run dry.
The fix is simple. Slip a mesh skimmer sock over your skimmer basket. It catches acorns and other small debris before they travel any farther into the system, and you just pull it out and dump it. Raking acorns off the deck and nearby grass a couple of times a week also cuts down on what blows into the water in the first place.
Heads Up: Check your pump basket every couple of days during acorn season. A pump that runs dry, even for a short time, can burn out the motor seal. That is a repair call, not a five-minute fix.
3 The Algae Connection: How Debris Feeds Green Water
Decaying leaves and acorns are food for algae. Add a few warm afternoons, and a pool that looked clear on Monday can turn cloudy or green by the weekend. The fix is staying ahead of it, not catching up after the fact.
Keep your chlorine steady and add BioGuard Algae Complete weekly through the rest of the season. It works as both a preventative and a treatment, so it handles debris-fed algae before it takes hold.
On a tighter budget, BioGuard Back Up is a lighter preventative option, though it will not treat algae that has already started.
BioGuard Tip: Had a heavy leaf day and need to shock the pool? BioGuard products only need 15 minutes before you can add your next chemical. Generic shock can make you wait up to 4 hours. That difference matters when fall daylight is short.
4 Your September Debris Routine
Split the work into daily and weekly tasks and it stops feeling like a full-time job.
|
Daily
|
Weekly
|
| Debris | Main Risk | Your Fix |
|---|---|---|
| Leaves | Staining, algae food | Skim daily, net at night |
| Acorns | Clogged basket, dry pump | Check pump basket often |
| Algae | Green or cloudy water | Weekly Algae Complete, steady chlorine |
If skimming every day sounds like a lot to keep up with, you are not the only one asking. We will cover how a robot cleaner earns its keep during leaf season in an upcoming article.
Falling behind on skimming, or found acorns in your pump basket? Stop by or give us a call. We carry everything you need to stay ahead of fall debris, because we make pool ownership a joy!
Call Us Now — 763-542-9000Written by Your Happy Dolphin Pool & Spa Team