Should I Drain My Pool And Start Over?
Should I just drain my pool and start over with fresh water? This is something that many pool owners have said, most especially new pool owners as chemical maintenance in swimming pools tends to have a learning curve. In the beginning of pool ownership chemical maintenance and water balancing looks a lot like magic, but experienced pool owners spend so little time fussing with the water chemistry that it would be hard to quantify how much time it actually takes them. Minutes, not hours. So why do so many new pool owners want to dump their old water and refill the pool? Simply because it appears that this would be the easiest course of action to fix pool water that has gone bad. Green water, brown water, cloudy or murky water...all reasons why someone might thing a fresh drain and fill might be the best option.
In the majority of cases draining and refilling is not the correct course of action to take to fix your water!
While the tendency to drain and fill the pool to fix water quality problems exists you need to realize that there are very few times where draining and filling your pool will be the right method to fixing your water quality problems. Very few. Pretty much any color of pool water can and should be fixed by properly adjusting the water chemistry. Even something as bad as fecal accidents in pools do not require draining but instead use a system of physical debris removal combined with a free chlorine increase between 2 to 20 parts per million depending on the nature of the accident.
Only rare cases, like having raccoons in your pool, are reason enough to need to drain and refill, and that is specifically due to the Baylisascaris procyonis roundworm parasite which can be found in raccoon feces. This worm is known to cause severe neurological illness in humans, especially children and extreme steps must be taken to sanitize pools contaminated with raccoon feces.
Aside from extreme biological contamination from parasites resistant to chlorine draining and refilling is almost never the right solution to fixing bad pool water. The problem in almost every circumstance results from a lack of understanding of swimming pool water chemistry and balancing. There are fundamental processes you need to follow, and specific values that you must achieve with your chemistry.
In almost all cases one or more of these values is well outside of the ideal range and as a result the rest of the pool looks like hot garbage. Fix the values and you will fix the water. It does take a little time for the water to clear up even after you have fixed the problem since the volume of water is so large so do not expect instant results when you make a correction to the chemistry.
Short list of "must do" steps to fix your pool water:
1) Run the pump and filter 24/7
2) Clean or backwash your filter when PSI rises 7 or more
3) Vacuum and skim all debris from pool
4) Adjust total alkalinity to 120
5) Adjust pH to 7.4
6) Check calcium hardness is 200 to 400 ppm
7) Adjust (and hold) free chlorine level at 2 to 4 ppm
In addition to these steps it will be important to also verify that you do not have a problem with CYA (cyanuric acid) or phosphates in your water. Either of these values being too high would prevent all of your hard work from paying off. Your CYA level must stay between 30 to 50 ppm. With CYA over 100 ppm the chlorine in your pool is not able to function. This is a common mistake made my new pool owners. Everything would be testing fine with your water, and yet the water would be green. Having even one value of your water chemistry out like this undermines everything else you are doing right and your water still ends up green. So CYA is needing to be 30 to 50 ppm and your phosphate levels should test under 500 parts per billion. Over 500 ppb and the phosphates will be encouraging too much organic matter growth in the water and you will have trouble holding chlorine levels and keeping your water clear.
In addition to phosphates and CYA levels you should also be aware that dissolved metals in the water can cause serious problems. For an example of this you can read this article on brown pool water to see how iron can turn water brown (suddenly) and can be a real pain to get rid of. You can have metals in your water from contaminated supply sources like rural wells, or you can also develop metals within the water from deteriorating metal components within a pool system. If you have an old heater that is rotting and failing internally then the metals within the heater leech into the water. They can cause staining slowly over time to the surfaces in your pool, or they can also change the water suddenly to a murky brown (or green as with copper) color right after you add some chlorine or oxidizer to the water.
If you are having problems with your water color, and quality, then you should have your water tested for copper and iron to see if you have a problem with these in your water that you need to deal with. Easily this could account for persistent water quality issues. Draining and filling will not fix this either, since the copper and iron is probably in your fill water supply, or some metal component within the pool system is corroding and will continue to be a problem with the new water as well.
If your water is green or you often struggle with having green water then watch this 10 minute video to learn about the different reasons that pool water might turn green and how you can fix it:
If you follow each of the steps above this will resolve 99% of water quality and clarity problems in swimming pools. Within 48 hours the pool will look significantly cleaner and within a week at most you will be able to see if there is a coin sitting on the deep end floor of your pool. More importantly, and this can not be stressed enough, most pools require special consideration to drain as draining your pool improperly can result in damage.
Why you should never drain a swimming pool!
If you drain your pool there is a very real chance that you will damage your pool. The damage for vinyl liner pools usually is limited to ruining the liner. Liner pools are never to be drained. Ever. For any reason. Once installed the water must stay in the pool at all times. Even if you had to drain a liner pool you would only ever partially drain and refill it. Never drain a liner pool. Even worse are concrete and fiberglass pools, which unlike vinyl pools require hydraulic balancing within the ground via a hydrostatic relief valve. If the pool is drained there is a very real concern for structural damage, cracks, twisting or even lifting out of the ground. Never drain a concrete pool or a fiberglass pool without consulting with a pool professional first.
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