by Rob Cox May 13, 2015
When the water temperature in your pool reaches the 60's, algae begins to grow at an accelerated rate, just as your winterizing algaecide and chemical floaters have expired.
If you have a mesh safety cover, sunlight can penetrate the fine mesh and warm the water, and if you have a high water level in the pool it will touch the center of the cover, warming the water even more, and even worse, trapping leaves and debris which leach into the pool water, like a giant tea bag.
Solid pool covers which are maintained during winter can be pulled off to a clear blue pool, but if there are holes, and it's covered in debris and water, this can contaminate the pool water.
Let's assume that you have a slightly green pool, and this is your first pool opening in your new home or with your new pool. Let's get started!
If you haven't already, drop a hose on the edge of the pool. Many pools may seem full under the cover, but it's a good idea to fill up the pool on the high side, because you will need to waste some water through backwashing or vacuuming to waste, except for cartridge filters. Use the skimmer opening or tile as a water level gauge. Normal pool level is mid-tile, or mid-skimmer actually, but you may want to add another few inches of water before or during pool opening.
At the Pool
At the Pump
Bring the hose around to the pool pump, or fill a 5-gal bucket with water to prime up the pump basket. Open the pump lid and fill the pump until water begins to run out or drain back to the pool. Replace the pump lid, tightening it very securely. Check that the filter valve is in the filter position and any return side valves are open. Close the main drain valve for now, and open the skimmer valve(s) fully. Open the air relief valve on the top of the filter, and with an eye on the pressure gauge, turn on the pump at the breaker and time clock or switch. If pressure spikes to 30 psi or higher, shut off the pump quickly and recheck valve positions, or for plugs left in the pool wall.
If the pump doesn't catch prime and begin pumping at full steam after a minute or so, shut it off and repeat the priming and starting process. If it still won't prime and catch, try starting off one skimmer only, or try opening the main drain valve. If you have a DE or sand filter with a multiport, you can place the valve on waste or recirculate for start-up. Pool pumps will catch prime more easily if the water isn't forced through the filter, and either waste or recirculate has less resistance to overcome. If it still won't catch, look for air leaks, usually from a loose pump lid, or loose pipe coming into the pump. A Drain King can be used to help prime a pump from the skimmer, and also to pressurize suction lines and pump to look for air leaks.
When the pump does start pumping water, you can slowly open the main drain valve, and very slowly pull in the air trapped in the pipe. For a DE filter, add a charge of DE powder immediately through the skimmer, with the filter valve in the filter position.
Close the air bleeder valve when it sprays a continuous stream of water. Note the filter pressure reading at start-up - this is your clean, starting pressure. Write this number, the clean psi reading, on your filter tank with a permanent marker, or make a mark on the gauge face with a Sharpie, as shown here.
Most pools that have been closed for six months look like it, so don't worry if it looks really bad when the cover comes off. Cleaning and chemicals will restore it - first you clean, then you add the chemicals. Start by cleaning off the pool deck with air or water, and then skim the pool surface with a Leaf Rake. After skimming the top and scooping any large piles of leaves on the bottom, vacuuming the pool is in order. If you don't have a vacuum hose and head, set-up the pool cleaner to do the job. Get rid of as much debris as possible before adding chemicals and brushing the pool.
Remove as much debris as possible - leaves, sticks, worms, etc., so the chemicals aren't wasted attacking a dead pile of leaves. Test your pH and Alkalinity levels first with a good test kit or strips, and adjust if needed so that pH level is 7.2-7.4 and Alkalinity is 80-120 ppm. Check also calcium hardness, to be sure that it's above 180 ppm, and cyanuric acid (aka stabilizer or conditioner), should be in the range of 20-40 ppm. If needed, add water balancers to adjust these 4 levels.
Now you can shock the pool with granular chlorine, at a rate of 1 lb per 10,000 gallons for a clear pool, or 2-4 lbs per 10,000 for a green pool, depending on how green it is, or just keep shocking the pool until the water turns a blue-grey color. Shock the pool in the evening, or after the sun has gone behind trees, and check the chemical levels again in the morning. If the chlorine level is non-existent, or zero, and the pool still looks 'meh - shock the pool again. Normally one treatment is enough, except for very poor water conditions.
For a plaster pool, pool shock can be poured around the edge or broadcast across the surface. For a vinyl pool, pre-dissolve chlorine shock in a bucket before adding, or use non-chlorine shock, which won't harm vinyl liners.
Run your pool filter 24/7 for a few days, checking on the filter pressure and water flow every 8 hours or so. Backwash sand or DE filters when the pressure gauge rises 8-10 lbs above the clean, start-up pressure. For cartridge filters, shut off the pump, remove the filter and hose it clean with a garden hose spray nozzle, when pressure has risen at least 5 psi, or flow is noticeably reduced.
When the water clears, you can set the timeclock to run 12-15 hours daily, increasing to 18 hours daily when water temperatures approach 80°. Maintain a constant chlorine level of at least 1.0 ppm, which takes about 3-5 of the 3" chlorine tablets per week for most pools. Check your pH at least weekly, and your alkalinity, cyanuric acid and calcium hardness levels at least monthly. Shock the pool every 4-6 weeks, or if algae is visible. If needed, algaecides and clarifiers can be useful accessory chemicals.
Keep the pool clean with regular skimming, vacuuming and brushing, emptying the baskets for the skimmer and pump, and servicing the pool cleaner if you have one. Check the filter and water level and condition every day when possible, to be sure all systems are operating A-OK! In most cases, once the pool is up and running and you get the hang of things, it usually will take you no more than 1 hour per week in maintenance.