Drain the Water
Turn off all the electricity going to your pool equipment so that when you drain the water, you don’t damage your pump, filter, pool or spa light, booster pump or heater. Place the submergible pump in your pool. Toss the output end up on the deck of your pool and then out into the street, if you are able to drain to the ocean. If you need to drain to the sewer, position the output hose into the backwash or the clean-out drain. Place the output hose into your toilet if you are not allowed to drain into the street or the sewer. If you use this option have someone watch carefully for overflow.
Resurface the Pool
Chip all the old plaster off with jackhammers or picks. Run the piercing equipment down the plaster, separating the old plaster from the original gunite structure (gunite is the type of concrete used for most swimming pools). You must remove all the plaster off the gunite entirely before you can start the resurfacing process.
Bathe the swimming pool shell in a light acid wash using 3 parts water to 1 part clean muriatic acid. Wash the entire pool down with the acid solution. Make sure there isn’t any loose material left on the swimming pool shell so that the new plaster will adhere to the gunite.
Place a full-size plaster mixer on the deck as close to the pool as you can get. Put your bags of plaster right next to the mixer. If possible, use more than one wheelbarrow for running the plaster from the mixer to the pool. Pour the plaster mixture into the pool. Have at least 3 to 4 finishers in the pool with trowels to immediately start spreading the plaster around and filling in the big voids. They need to be wearing shoes with spikes on the bottom so that they don’t leave footprints in the plaster and walk around the pool without slipping as they resurface the area Smooth in the first coat, known as the scratch coat. The main purpose of this coat is to set a foundation and to get the bigger nicks filled in. Let it set.
Toss a quarter into the pool. If it sticks, it is not time to add the second coat. If the quater bounces, fire up the mixer–it’s time for that second coat. The second coat is the main coat. The third coat is the finishing coat.
Refill the Pool
Perform the quarter test 1 more time to make sure the plaster is dry. Procure a water hose. Make sure there is no water that could spill out of the hose. Tie a rag or an old sock around the end of the hose over the hardware so that it won’t scratch the new finish. Walk into the pool with double or triple socks on your feet so there are no hard ends and you leave no scuffs in the plaster.
Place the hose, gently, all the way down at the bottom of the pool.
Replace your drain covers, pool lights and make sure there is no water anywhere running down the sides of your pool, which could make a line on your new finish.
Turn the water on so the hose will start filling the pool from the bottom up. Once you start filling the pool, you cannot stop it before it is done or the water will create a permanent line in the plaster finish where you stopped. You must fill the pool all the way up as quickly as possible.