How to Drain Water from the Pool without Using a Submersible Sump Pump to Reduce CYA

[00xavier]

I contacted my pool company today about replenishing 1/3 of the water in my pool to reduce CYA levels, which are currently at 90. They recommended two methods that do not require a submersible sump pump.

1. The first method requires that I shut off my pump for 3-4 hours. Next, I would place an old sock around the end of a garden house (to filter the water from the hose), tape it shut with electrical tape, drop it to the bottom of the pool, turn the water on, and force the old water out the overflow mechanism.

2. The second method involves turning off the pump, turning off the skimmers, and switching the filter to waste to drain 1/3 of the water from my pool.

I am in Houston and it is pretty hot out here. The pool company prefers the first method because it keeps water in the pool at all times and reduces the risk of filming around the pool that can occur when you drain it.

Which method is the best?

 

[RobbieH]

The first method will work, but as you have probably figured out it has diminishing results as you continue to replace water. In other words, it will require more water to do the replacement compared to draining to a point then refilling.

I don't understand why they want you to turn off the pump for 3-4 hours before starting the hose though.

 

[00xavier]

Do I need to wait 3-4 hours before starting the hose? What are the risks to the second method?

 

[jblizzle]

There is no reason I can think of to wait any amount of time.

There is not too much risk ... you do not want to drain the water below the ground water level (may not be applicable to you) and you do not want the pool surface exposed to the sun why dry. If you drain to waste in the evening and start filling overnight, it will not be exposed to the sun much at all ... and you could just keep spraying the walls to keep them wet.

 

[dfahrion]

I did something similar to #1 to lower CYA in our pool. The idea is the cold water from the hose should stay at the bottom and not mix too much with the warm pool water. It worked well for me for around a 50% reduction, but since salt water is also denser than fresh I don't know if it would work very well to reduce the salt level or not.

The only reason I can think of to wait after stopping the pump is in our pool the pump gets a pretty good current going in the pool and it can keep turning in the pool for several minutes after stopping the pump, but 3-4 hours would be overkill for that. I also don't understand why you would filter the hose water with a sock, isn't that the water you drink?

You should also check on anti siphon laws in your area before throwing the hose into the pool. One idea to get around that is to use the vacuum hose with the weighted vacuum attachment to hold one end at the bottom of the pool, elevate the other end of the vacuum hose and put the water into the top of that. Keeping the water hose above the level of the pool along with the bigger diameter of the vacuum hose should give you enough of an air break to keep the water system "safe" while still adding the water to the bottom.