Maintaining Pool Water Quality - The 5 Things You Must Know

You've bought your fibreglass pool direct (or through a full price pool builder) and now your sparkling pool water is looking a little cloudy, the local pool shop has rows and rows of chemicals that fix problems you've never heard of and your not really sure what you are supposed to do. Sound familiar? Yep, that's how 90% of new pool owners feel. So let's explain water quality maintenance in plain English shall we?

With your fibreglass pool up and running, maintaining your water quality is really important for both bather comfort and your warranties. It can seem like you need a Chemistry degree. However if you read the 5 key elements to water quality below, you'll be talking like an expert in no time! Why do I need to know this stuff? Well, if you prefer crystal clear water, happy swimmers and spending your time in the pool rather than at the pool shop buying more chemicals, read on. If you are Shrek and you like algae, green water and unsafe swimming water, you can stop reading now!

Ongoing Water Maintenance for Fibreglass Pools - to ensure that your pool uses the least amount of chemicals and to maintain your pool and equipment warranties, it is important you test your water quality (weekly in warmer months and every two weeks in colder months) to maintain the following critical elements. 

  • pH Level: pH measures how acidic or alkaline your pool water is and is one of the most important elements to keep within the recommended range.
    Why is this important? Unbalanced pH levels can cause skin irritation, eye soreness, impact chlorine effectiveness, damage the gel coat surface and damage your pool equipment seals and plastics. This can potentially void warranties. Maintaining the right pH levels will solve many common issues with pool water maintenance and is always the starting point to get right before adding other chemicals. 
    Our Manufacturers Recommended Range: 7.2 - 7.4
  • Total Alkalinity: alkalinity measures the total amount of dissolved solids (bicarbonates, carbonates and hydroxides) in your water and acts as a buffer against changes in your pH levels. Think of it as a mood stabiliser for your pool pH. Steady levels are better than peaks and troughs.
    Why is this important? Low alkalinity can destabilise your pH levels causing the issues we just talked about. High alkalinity can result in high pH levels which reduces the effectiveness of your chlorine and can cause cloudy water and scale formation in your pool and equipment. Scale will reduce the operational life of your equipment, particularly your pump which can hit you in the back pocket. 
    Our Manufacturers Recommended Range: 80 - 120 parts per million (ppm)
  • Calcium Hardness: measures the amount of calcium dissolved in your water.
    Why is this important? Low calcium hardness can cause your water to become corrosive which affects pH stability. High calcium hardness causes calcium deposits to form on your your pool walls and equipment. This can damage the gel coat surface of your pool and shorten the life of your pool equipment as well. Think of calcium deposits like tooth plaque. Better to prevent them forming than going to the Dentist for the dreaded "scale and clean". As a note, Dentist's don't usually scale and clean pools.
    Our Manufacturers Recommended Range: 120 - 300 ppm
  • Chlorine Level: chlorine kills algae, bacteria and germs present in your water. It is your Number 1 defence against water bugs and not worrying about your kids. If you bought your pool direct through us, your gelcoat has an exclusive built in anti-microbial (Eco-Pure) which reduces the amount of chlorine you need to sanitise your water. However, you still need chlorine. Chlorine is a consumable and needs to be continuously supplied through your chlorinator to maintain safe swimming water. 
    Why is this important? Warm weather and low chlorine levels will allow algal blooms and bacteria to grow in your pool. Direct sunlight (UV exposure) kills chlorine (a pool blanket eliminates a lot of this and prevents water evaporation) and the higher the bather load (number of swimmers) regularly using your pool, the more chlorine your chlorinator will need to produce to maintain safe sanitation levels. If you are having a pool party with 10 kids, turn up your chlorinator for a day or two after the party to build your chlorine levels back up.
    Our Manufacturers Recommended Range: 1.5 - 2.5 ppm
  • Stabiliser: stabliser is a chemical (cyanuric acid) that acts like sunburn cream for your pool water which reduces the amount of chlorine killed by UV light from the sun. It is most effective in the summer months when UV light is at its highest levels, however, you need stabiliser year round.
    Why is this important? If your pool is in direct sunlight for much of the day and you don't have a pool blanket, UV light can kill most or all of the chlorine your chlorinator is producing. Yes, you can turn up your chlorinator to the maximum setting, however, this means you are working the chlorine producing cell much harder than needed and you will shorten the cells operational life. At between $350 and $500 to replace a cell, stabiliser is a lot cheaper. Without stabiliser, if you have several sunny days, then overcast conditions and back to sunny again, your chlorine levels are going to fluctuate in and out of range which will invite algae, phosphates and other critters into your water. Prevention is better than cure with any of these, as you need to add algicides, flocculants and other expensive chemicals along with the extra time needed to cure your suddenly unwell pool. 
    Our Manufacturers Recommended Range: 30 - 50 ppm

What Is The Easiest Way To Have Your Water Tested?

Your handover kit included with your pool from us has a 4 in 1 test kit. These have been used since the Pharaoh's checked their pools. I might be slightly colour blind, however, I was never quite sure if the test strip colour matched the dark purple, slightly less dark purple, light purple or purple, purple colour indicating what my pH level was. In brief, they are better than nothing, however, it is really a guesstimation.  You'll know when you got it wrong when the kids tell you their eyes are stinging! Ooops, sorry girls (I have two daughters). 

Your local pool shop will usually offer free water testing and provide you with a water sample bottle (or use one of your kids old water bottles). They'll give you a print out of the test results in a couple of minutes and recommend what you need to do to maintain your pool water (they will of course happen to sell all of the required chemicals!). A weekly trip to the pool shop to test your water is part of pool ownership!

Or, if you have an Astral Smart Plus Analyser, once calibrated to your pool water volume, it will continuously measure the critical elements of your water mentioned above. You can see from your smartphone at any time what those levels are for complete peace of mind. If the kids want to jump in the pool after school and you're not sure if your water is safe, check the app and give your kids the thumbs up or thumbs down. I wish I had this analyser gizmo when my kids called me back in the day and I had to say "I haven't had the water tested and I'm not sure if it is safe to swim". Cue upside down smiles from said kids and a mad dash to the pool shop after work to get the water tested.

The Smart Analyser will also automatically send you a message advising you that your pool needs attention and what needs to be done. i.e add 120ml's of acid to adjust your pH levels. As one customer said to me "I don't miss going to pool shop every week now I've got that gizmo thing" (meaning the analyser!) Get in touch if you would like a price on the gizmo thing and you don't need to have bought a pool direct through us to buy equipment from us (which we guarantee is at least 25% below the retail price).

Why Am I Using So Much Chlorine andChemicals ?

Assuming your filter is regularly cleaned and is the right size for your volume of pool water, the usual culprit is dilution. Any time freshwater is added to your pool, you will need to add more of each chemical to bring your levels back into range. If you are having to continuously top up your pool water after the kids expressly forbidden bombie competitions or there has been heavy rain, your water will be diluted which will need more chemicals to rebalance your water. If you don't have a pool blanket and you are continuously replacing water lost through evaporation, it is the same issue of dilution. Remember with evaporation, wind causes more evaporation than heat.

If you are running your chlorinator (assuming it is the right size for your pool volume of water) on the maximum setting and only just make it to the minimum chlorine level, chances are UV light is killing your chlorine if you haven't used stabiliser, you have phosphates in your water (which eats chlorine) or you are not running your pump for long enough. 

What About Mineral and Freshwater Pools?

Mineral pools and freshwater pools still have chlorine, albeit at much reduced levels, so you will need very little, if any, stabiliser. (I know, the box said "no salt" or "no chlorine" pool water. The best freshwater systems still have chlorine at the same level as your tap water. Check the fine print!)

You still need to test for pH, alkalinity, calcium hardness and chlorine levels. Make sure you tell your pool shop your pool is either mineral or fresh water as they will adjust their water test. The Smart Analyser has a mineral pool setting so check this field for accurate readings. If you have a mineral or freshwater pool, the 4 in 1 test kit is designed for salt water chlorinated pools. Use the test kit provided by the freshwater or mineral equipment manufacturer. 

What is The Difference Between Saltwater, Mineral, and Freshwater Pools?How to Prepare Your Pool For an Australian Winter?

Rohan Taylor
About The Author

Rohan Taylor

My wife and I grew up playing in swimming pools. Our daughters learnt to swim in our backyard fibreglass swimming pool. There is nothing quite like hearing kids splashing about and giggling. As pools do, our pool became a social magnet for friends, family and neighbours which we loved. Helping customers to have their own pool and saving customers thousands on their pool and equipment is the best job in the world.

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