Cedar fever season in the Texas Hill Country is miserable enough on its own — red eyes, relentless congestion, and the creeping sense that you should move somewhere with different trees. But while you're suffering through it, your pool is suffering too. Cedar pollen (from Ashe juniper, the dominant tree species across the Edwards Plateau) is one of the most disruptive seasonal events for pool chemistry in our region, and most pool owners don't realize how quickly it can flip a crystal-clear pool into a murky, algae-prone mess.
Why Cedar Pollen Hits Pools So Hard
Not all pollen affects pools equally. Cedar pollen has a specific combination of characteristics that make it particularly destructive:
Fine particle size
Cedar pollen grains are small enough to pass through standard pool filters. This means they can stay suspended in the water for days without being caught, slowly breaking down and releasing their chemistry into the pool.
Acidic chemistry
When cedar pollen dissolves in water, it releases organic acids that drive pH down — sometimes dramatically. During heavy pollen events, we routinely see pH drop from 7.4 to 6.8 or below within 24–48 hours. A pH below 7.0 is corrosive to pool equipment and irritating to swimmers' eyes and skin.
High phosphate content
Cedar pollen is rich in phosphates, which are the primary nutrient source for algae. A heavy cedar pollen deposit is essentially fertilizing your pool for a bloom. Phosphate removers, which we don't use year-round, become part of our standard treatment during cedar season for exactly this reason.
High chlorine demand
The organic material in pollen consumes free chlorine rapidly. A pool that stays sanitized at 2–3 PPM normally can see that drop to near zero within a day of heavy pollen fall. Without adequate chlorine, the algae that the phosphates are feeding has nothing standing in its way.
The Untreated Cedar Season Timeline
This is how a cedar pollen event typically unfolds in an unmanaged pool:
- Day 1–2: Pollen settles on the surface and begins dissolving. pH starts dropping. Water may look slightly hazy.
- Day 3–5: Chlorine falls significantly. pH may be well below 7.0. Phosphates are rising. The pool is now a favorable environment for algae.
- Day 5–7: Green tint appears. You're in algae bloom territory. Recovery now requires significantly more time, chemicals, and cost than prevention would have.
Our Cedar Season Defense Protocol
We adjust our standard service during cedar season — typically December through February, with peak pollen usually hitting in January:
- More frequent pH checks. We monitor pH at every visit and may recommend mid-week spot checks for pools in heavily wooded areas or near large cedar stands.
- Phosphate removers. Added during cedar season service visits to starve out early algae before it becomes visible. Not something we use year-round — but essential from December through February.
- Preventative algaecide. A low-dose algaecide application during peak pollen events disrupts early algae formation before it gains a foothold.
- More frequent filter cleaning. Cedar pollen is hard on filter media and cartridges. We clean or backwash more frequently this time of year to keep filtration effective.
- Acid additions as needed. If pH is dropping between visits due to pollen load, we add pH increaser or adjust acid dosing to compensate for the organic acid input from pollen.
What You Can Do Between Visits
A few simple things homeowners can do during cedar season that make a real difference:
- Skim the surface daily. Removing pollen before it dissolves is the single most effective thing you can do. A pool cover helps significantly if you're not using the pool.
- Run your pump longer. Increase daily pump run time to 10–12 hours during heavy pollen events to improve filtration and circulation.
- Check pH twice a week. A basic test strip or drop kit costs less than $20. If pH falls below 7.0, add pH increaser and let us know.
- Don't skip service. Cedar season is the worst time for a service gap. One missed week during peak January can be the difference between a clear pool and a green pool that takes several visits to recover.
If Your Pool Has Already Gone Green
If cedar pollen has already gotten the better of your pool, it's fixable. Our green-to-clean recovery process typically involves:
- High-dose shock treatment to kill active algae
- Brushing and vacuuming to remove dead material
- pH balancing and phosphate removal
- Filter cleaning
- Follow-up visit 48–72 hours later to confirm clearance
Most green pools are back to swim-ready within 3–5 days with proper treatment. Contact us for a green-to-clean quote — we do them year-round, no judgment.
The Bottom Line
Cedar season is predictable. It happens every year, in the same months, with the same effects. The difference between homeowners who glide through it and those who call for emergency green pool service in February is almost always proactive maintenance.
If you're heading into cedar season without a service plan in place, reach out before the pollen hits. It's much cheaper to prevent the problem than to clean it up.