There are several things you should NEVER do with or to your swimming pool. As professionals, we know what works and what doesn't. For the safety of you and the longevity of you pool, please follow these DON'Ts (and I'll explain why):
Don't drain your gunite, concrete or one piece fiberglass swimming pool...
Your pool may seem big, but compared to the earth, it's a tiny pin prick to the surface. And what's underneath the surface, the potential for literally millions of gallons of water that can or will lift the pool body up out of the ground. Talk about pool dangers!
You can clearly see from the picture on this page the damage that was caused because the homeowner, without experience, decided to "save some money" by draining, cleaning (acid washing) and servicing their own pool without taking into consideration the local flooding or heavy recent rains or the possibility that there was a curtain drain around or under the pool (known as a "hydrostatic relief valve") and not using it. After the pool drained, the underground water lifted the pool up damaging plumbing lines, tile, coping, the pool structure itself.
All that was necessary to do was to attach a pump to the pipe of the hydrostatic relief valve and allow it to pump excess underground water out from under the pool and away, and then allow the ground to DRY OUT for several days before attempting to drain the pool for servicing. Although most pipes for hydrostatic relief valves are hidden away, your builder or pool service company should know where it is.
Vinyl liner pools may not "pop" out of the ground, but the liner could "float".
Because a vinyl liner is flexible and only attached at the top coping receptor and at the various wall fittings - skimmer, returns, suctions, auto cleaner fitting, lights, acrylic steps - the liner can move as ground water accumulates underneath it. Depending on the volume of ground present, that will determine how much or how badly the swimming pool liner can float.
In areas where there is known ground water, the original builder hopefully installed a hydrostatic relief valve to alleviate and draw away that ground water. But often times, the builder, no matter how accomplished and competent they are, may not know of underground streams or "ponds" because those problems only surface when the conditions are extreme; post hurricane, for example.
Because the vinyl liner is flexible, it will usually go back to its original position, but more than likely with a few wrinkles. The wrinkles aren't harmful or dangerous, they just look bad. Depending on the age of the liner, a seasoned vinyl liner service company or technician should be able to properly re-install the liner with minimal fuss. This is something that you as the homeowner do not want to do. If the vinyl liner is left without water for a time (could be days or even hours), the liner will eventually shrink to the point where it cannot be reinstalled.
When you hear of potentially poor weather with lots of precipitation (think of a hurricane or seasonal flooding), it would be a very good idea to locate that pipe from the hydrostatic relief valve, attach a pump to it, and begin removing the existing or accumulating ground water to prevent the liner float & avoid pool dangers.
Be sure to check with your builder or local professional.
Can you "mix" pool chemicals? The answer is "yes" and "no". Improperly mixing chemicals is one of the primary pool dangers. Let me explain...
When we refer to "NOT mixing pool chemicals" we're trying to be specific about NOT mixing different chemicals in the same bucket (a potentially volatile situation) as opposed to adding or mixing various pool chemicals into the body of the pool itself (very usually not dangerous).
Here's an example of what NOT to do... Some years ago a customer came into our store telling me that she had a problem with how she was treating an algae problem with chlorine shock & algaecide. Her words were something to the effect of "I mixed the shock & algaecide in a bucket and it began fuming and smoking with a bad odor, so I threw the whole thing into the pool..."
Shock treatments, in any form, are oxidizers. As an oxidizer, whatever the oxidizer is, always wants to oxidize whatever it comes into contact with. Chlorine, in almost any form but especially as granular product, is highly volatile and so when you literally mix a granular chlorine shock like calcium hypochlorite (even one pound) with just a couple of ounces of an algaecide will result in a fire at least or a possible explosion.
Here's the bottom line: ALWAYS ADD CHEMICALS DIRECTLY TO YOUR SWIMMING POOL WATER. Unless directed by your local pool care professional, never pre-mix chemicals; it's not necessary and it could be potentially dangerous.
Absolutely, positively not!
Why? As you can see, damage will occur to the pool pump & its parts. A dry running pump can get so hot as to melt baskets & other internal pump parts.
This may not seem like one of the several real pool dangers, but don't risk damage to any swimming pool equipment.
Not balancing the swimming pool water can be one of the great pool dangers.
Without going into great & gory detail, neglecting the pH, Total Alkalinity, Calcium Hardness of your pool's water can and ultimately WILL lead to some of the following serious problems:
1. Pool equipment & surfaces:
2. Physical health; I've witnessed the following over the years from customers who have neglected pool water balance
3. Environmental or pool areas
Sadly, too many people take safety and their swimming pool for granted. When the pool has a broken or missing wall fitting, especially a suction fitting (usually on the pool side wall) or main drain (pool bottom drain), it must be replaced as soon as possible to avoid the risk of injury, even death, to someone who may get caught or trapped by that fitting. This is one of several incredible pool dangers that is preventable.
Several years ago, the US Congress passed a law known as the Virginia Graham Baker Pool & Spa Safety Act (known in the industry as VGB) in response to a child drowning in a residential swimming pool. Even in shallow wading pools, children will sometimes sit on the main floor suction simply because it feels nice. Unfortunately, the suction or flow of the water may (without a proper grate fitting) could lead to disembowelment or long hair being drawn into the suction fitting, pulling the person underwater and trapping them.
Wall fittings, especially suction fittings or grates must be changed every 5 to 7 years. Plastics don't last forever; plastics break down and become brittle (especially when the water is out of balance), thereby cracking and breaking allowing large gaps where hair and body parts can become trapped.
When re-plastering or painting or replacing the vinyl liner in your swimming pool, be sure that your builder or service company is replacing those suction faceplates. Then, it's YOUR responsibility as the homeowner to replace them down the line for the safety of everyone using your swimming pool.