How Full Should My Pool Be With Water?


Does A Salt Water Pool Chlorinator Monitor Chlorine?

One of the biggest concerns for salt water pool owners is water chemistry: Keeping all water measurements like salt, chlorine, pH etc within the desired range to maintain water sanitization and cleanliness for swimming. When water is added or removed from the pool, it can throw water chemistry out of balance.

While each pool is designed to hold a certain volume of water in gallons or liters, a quick guide to determine ideal water level is to look at the skimmer on the side of the pool and try to maintain a water level about 1/2 up the skimmer if not a bit higher to account for evaporation and other water loss. When the water level is higher than the top of the skimmer, it can’t actually skim debris off the surface of the water. When the water level drops close to or below the bottom of the skimmer, the skimmer opening can be starved for water and introduce air into the system which negatively affects suction.

What is the ideal water level for your salt water pool?
Keeping the water level about halfway up the skimmer like in this picture ensures that there is enough water for the skimmer to draw from while also not being too high that the surface of the water level can’t flow into the skimmer to be cleaned.

Draining Water From The Pool

You might be amazed to learn how much water can evaporate in a pool each day. Hot sunny weather might see 0.25 inches of water lost per day which means up to 1.75 inches of water per week. This could equate to up to 70 gallons of water per day lost for a reasonably sized family pool.

So before you drain pool water because you think the water is a bit high, first do the skimmer test mentioned above to check to see how high the the water level is. If it’s borderline and slightly high but still below the top of the skimmer, unless I’m getting heavy rain in the next few days, I’m probably doing nothing.

While I have seen heavy summer rain increase water level significantly after a downpour that results in the water level going higher than the top of the skimmer and necessitated draining water, I tend to leave things as they are unless the water height is really too high. Between evaporation and pool use, the water level often drops quickly to a more reasonable level to the point where it might not be long before you’re contemplating adding water to top it back up.

I can think of one occasion where we had so much rain over several days in the summer that I actually ran out in the rain and set the hose up in the pool to siphon water out of the pool as it was still pouring. The water level in the pool had gotten so high, it was above the top of the skimmer opening.

Ideal Pool Temperature

For many backyard pool owners, you’ll probably find that the average temperature for swimming is between 78°F and 82°F. Many pool owners don’t own a heater so they rely on the sun and perhaps a solar blanket at night to keep the pool warm enough to swim in.

The “ideal” pool temperature may depend on the person, their age and what specific swimming activity they are taking part in. The United States Water Fitness Association suggests the following pool water temperatures depending on age group and type of pool usage:

Highly Competitive Swimming Teams:78 to 80 degrees
Swimming Lessons (beginners) 
Preschool:
3 – 5 years:
6 – 13 years:
Adults: 
88 to 94 degrees
86 to 90 degrees
84 to 86 degrees
85 to 89 degrees
United States Water Fitness Association

The United States Water Fitness Association also suggests that the average multi-purpose pool in the US has a range of 84 – 84 degrees.

Chlorine Production And Temperature

A salt water chlorinator will generally shut down or at least automatically slow down chlorine production once the water has gone below a certain temperature. At 60° Fahrenheit your chlorinator may automatically decrease the time that it produces produces and at 50° Fahrenheit it may shut chlorine production down completely. Once below that temperature, pool water is safe from algae and doesn’t need chlorine to protect against it. Plus at that low temperature, the salt cell has to work extra hard to convert salt to chlorine and isn’t very efficient at doing so.

How Deep Should A Pool Be?

The depth of your pool should match your desired use. Are you a diver that needs a deep pool or are you just swimming and splashing around mostly for fun?
The depth of your pool should match your desired use. Are you a diver that needs a deep pool or are you just swimming and splashing around mostly for fun?

If you’re building a pool, two of the biggest decisions other than shape of the pool is the size (dimensions) and the water volume (depth). Not surprisingly, the bigger and deeper the pool the more you’ll pay and the more water you’ll use to fill it. The deeper the pool, the more digging that needs to be done and that’s a big cost of pool building.

Think carefully about a few things related to pool depth, namely:

  • What are your desired swimming habits? Are you going to be diving daily and need an 8′ pool or can you get by with a 6′ plunge pool that meets your needs and costs far less?
  • What is the resale potential of the pool you’re planning if you ever decide to sell your home? You might like the idea of a smallish plunge pool but will it be appealing to a young family who want a diving pool?

Try your best to and research existing homes with pools in your area and see what people generally build. Some areas of the country may have different preferences and may choose different styles depending on weather patterns, etc. The last thing you want to do is end up with a unicorn pool that suits you but no one else.

Pool Water Jet Positioning

Pool water return jets send water that has been freshly filtered and chlorinated back into the pool for use. Typically a residential pool will have 2 return jets: One in the deep end and one in the shallow end. They are screwed into the fitting on the wall of the pool and generally are left to point downwards so they shoot water at a high rate towards the bottom of the pool.

By aiming the water jets towards the bottom of the pool, it does a few things. It keeps the water still on top since the aim of the water jet is in the opposite direction. Secondly, it helps to keep water flowing and moving throughout the pool. Certainly in the case of the shallow end which isn’t typically very deep, it helps to keep water moving on the bottom of the pool so debris can’t settle.

This is one of the things I have to admit, I like playing around with from time to time. I sometimes turn one return jet up towards the top of the pool which has the effect of creating a kind of whirlpool effect throughout the pool. The top of the water throughout the entire pool starts shimmering and makes a water fall type sounds which I like hearing. I just think it’s a cool thing to do for a few hours here and there. I generally do this in the evening when the sun is down as it’s nice to hear the sound of the water in the dark.

Scientifically though, you should point your water return jets downwards for the two reasons mentioned above. But also because you minimize the surface area of the water which reduces evaporation and by pointing the jets downward you are circulating recently chlorinated water in the opposite direction and away from the sun. Direct sunlight kills chlorine so keeping the newly chlorinated water on the bottom of the pool is actually preferable.

Want to learn more about chlorine production in colder weather?

Carl Mueller

I bought a home with a salt water pool in 2006 and soon realized the benefits over traditional chlorinated pools. On this website I'll discuss all the tips and tricks I've learned over the years. I'll also help you troubleshoot various problems with pools in general and ones specific to salt water pools that I've experienced personally!

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