The honest 2026 answer: if you want to swim by Memorial Day weekend in Southeast Michigan, your pool needs to be uncovered, balanced, and heating by the first week of May. Wait until mid-May and you are racing the calendar. This is the checklist we walk through with every Anderson Brothers Pools service client — in the order that actually matters.
Two weeks before opening: the prep that saves headaches
The clients who have the smoothest openings are the ones who do small things in late April. None of this is glamorous — all of it shortens opening day.
- Clear the deck and cover. Hose off leaves, twigs, and the layer of pollen that always coats covers in spring. A clean cover means clean water when you pull it.
- Pump cover water down to the cover surface. A submersible pump or a cover pump handles this. Pumping standing water off the cover before you remove it keeps debris out of the pool.
- Check your equipment pad visually. Look at the pump, filter, heater, and salt cell or chlorinator. Any obvious cracked PVC, separated fittings, or rodent damage? Catch it now, not on opening day.
- Order chemicals. Stabilizer, alkalinity increaser, calcium increaser, shock, and either chlorine tablets or salt (depending on system). Pool supply shelves get thin in mid-May.
- Plan your fill water. Most Michigan municipal water needs metals control on first fill. Have a sequestrant on hand.
Opening day: the order of operations that actually works
Veteran pool service techs follow the same sequence every time because skipping a step costs you a day. Here is the order we use on Anderson Brothers pool service calls:
1. Remove the cover (carefully)
Two people, slow pull, fold as you go. If water is still on the cover, get it off first. Once removed, hose the cover clean on the grass, fold it dry, store it where rodents cannot reach it.
2. Reinstall the pieces you stored over winter
Eyeball returns, skimmer baskets, ladder rails, handrails, the pool light niche cover, drain plugs in the pump and filter. Anything you took out for winterization goes back in now — before you turn the system on.
3. Bring the water level up to mid-skimmer
Pools shed an inch or more of water across winter. Top up to the middle of the skimmer opening, not the top, not the bottom.
4. Prime the pump and start circulation
Fill the pump basket, replace the lid, open all valves on the suction side, start the pump on low. It should catch prime within 60 seconds. If it loses prime repeatedly, you have an air leak on the suction side — usually a dried-out o-ring at the pump lid or a drain plug you forgot to put back.
5. Run the filter for 12–24 hours before adding chemicals
Cold winter water carries fine sediment in suspension. Running circulation first lets the filter pull most of it out so your chemistry adjustments aren’t fighting muddy water.
6. Test, balance, shock — in that order
Test alkalinity first, then pH, then calcium hardness, then stabilizer. Adjust those four before you touch chlorine. Then shock to roughly 10x your free chlorine target to break down any spring algae starting under the cover. Run circulation overnight.
7. Brush walls and floor, vacuum, retest in 24 hours
Brushing knocks loose any algae getting a foothold. Vacuum settled sediment to waste if your filter has that valve position. Retest the next morning. Most pools need a second round of chemistry adjustment 24 hours after opening.
The Michigan-specific timing math
Here is the calendar that gets you swimming by Memorial Day weekend without rushing anything:
| Day | What happens |
|---|---|
| April 28–30 | Clean cover, prep equipment pad, order chemicals |
| May 1–3 | Remove cover, reinstall parts, prime pump, run circulation 24 hours |
| May 4–5 | Balance chemistry, shock, brush, vacuum |
| May 6–12 | Filter runs daily, water clears, chemistry stabilizes |
| May 18–22 | Start heater, raise water temp 3–5°F per day |
| May 23–26 | Memorial Day weekend: ~82°F water, ready to swim |
Run that calendar backwards from your target first-swim date. If you want to swim Memorial Day, today is the day to start.
What goes wrong on Michigan openings — and how to dodge it
Cracked plaster you didn’t know about
Late-winter freeze-thaw can open small cracks in older plaster, especially around steps and the deep-end coving. You will see them as hairline darker lines once the cover comes off. Small cracks can wait until next remodel; growing cracks should be evaluated — see our pool remodeling page for what a full resurface includes.
Stained walls from metals in fill water
If you topped up with hose water and skipped sequestrant, you may see brown or greenish staining from iron or copper. Treat with a metal-control product before you raise pH or you will set the stain permanently.
Pump motor that hums but does not spin
Most common opening-day surprise. Bearings froze. The motor needs replacement — not the whole pump in most cases. Order the part the same morning you find it; mid-May is when these get backordered.
Salt cell reading “low salt” when salt is fine
Cold water reads as low-salt on most salt cells. The cell will start producing chlorine normally once water hits about 60°F. If you are below that, supplement with liquid chlorine for a week.
When to call a pro vs. open it yourself
If your pool is straightforward, your equipment worked fine at closing, and you have opened it before, opening yourself is reasonable. Plan on a full Saturday plus chemistry follow-up.
If any of these apply, save yourself a week and have a pro do it:
- You have new equipment installed last fall and have not started it yourself yet.
- You see green or murky water under the cover.
- You hear anything unusual at the equipment pad — humming, grinding, or hissing.
- You winterized the pool yourself and aren’t 100% sure which plugs came out.
- You want a documented startup before you list the home or warranty-out a recent build.
Our service team handles openings across Birmingham, Bloomfield Hills, Troy, Rochester, Novi, Northville, and the rest of Southeast Michigan. Call 248-380-7665 to get on the route — the calendar fills end of April.
What to do next
Put the prep on the calendar this week. If you are doing it yourself, the timing math above is what hits Memorial Day. If you want us to handle it, call or message us — the earlier in the month the better the slot.
Frequently asked questions
When should I open my pool in Southeast Michigan?
If you want a Memorial Day first swim, plan to remove the cover and start circulation no later than the first week of May. Earlier is fine; later starts a calendar race against rising algae pressure and chemical balancing time.
How long does it take to heat a Michigan pool in May?
From early-May water temperatures of roughly 50°F to a swim-ready 82°F, plan on 24–48 hours of heater run time for a typical 20,000-gallon pool with a 400K BTU gas heater. Solar covers cut that time meaningfully and reduce loss overnight.
Can I skip the cover removal and have someone do it?
Yes — our service crews do dozens of openings every spring across Oakland, Livingston, and Western Wayne counties. Book before mid-April for the best dates.
My pool was green under the cover. What now?
Filter first, balance alkalinity and pH, then shock at 10x your normal free-chlorine target and brush walls. Most green opens clear within 48–72 hours of continuous filtering and a second shock dose. If it does not, call us — you may have a phosphate or stabilizer issue masking the algae kill.
Do I need to do anything if my pool was professionally winterized?
You still need to reinstall the pieces that came out for winter (eyeballs, drain plugs, baskets), bring water up, and balance chemistry. A pro winterization sets you up for an easier open — it does not eliminate it.
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