Pool water and the Drought

[Poolguy]

Significantly, this year follows a more typical trend for the weather, or at least the rainfall - or rather lack of it.

Water from the heavens when it does come, brings along with it, mineral and chemical contaminants from the atmosphere, some of which is from human activity but most is just from the environment.

So when it comes to the summer and there has not been enough rain to swell to the reservoirs nor enough to irrigate the crops, some strange thinks start to happen. That is, this year it seems to be stranger for pool water quality than for a long time.

Pools in western France have been eating Bicarbonate soda, OK that is not so strange and can be simply explained, but I've now presided over the 4th pool with significant Phosphate and nitrate contamination - I mean that some of them have been off the scale, more than 20mlg/lt. Inevitably, the pools are green in every case and do not respond to normal levels of chlorine or even standard Choc dosing. That is not normal.

So my remarks are aimed at pool owners who are facing a greenie where there is no rational explanation - that is, that your normal chemical levels are correct (all 4). If this is true in your case, its possible that you are among those to receive agricultural contamination which will cause the algae to grow up to 1 million times faster and appear to be Chlorine resistant.

[img]http://i584.photobucket.com/albums/ss285/andrewhenderson/Pools/Phosphatetest.jpg[/img]

Vile on the left, Municipal drinking water 0.3mlg/lt, phosphate
Vile on the right, Pool water nearly 2mlg/lt, phosphate

To fix it you have choices but they are far fewer than normal owing to the ban on refreshing pool water levels - water is scarce so you cannot go the easy route and change the water to reduce the concentration of phosphate and nitrates. As they are not metals you also cannot sequest, so we are into the territory of SUPER CHLORINATION. To do this I strongly recommend that you choose an expert with special and accurate testing equipment as not everyone can measure over 10mlg/lt of Free chlor, much less, nitrites, nitrates, or phosphates. If you try it yourself there will be a number of risks that will challenge you.

First, how much, the contaminant has to be identified and then measured so that sufficient chlorine added to reach ‘break point’; That is, the point when the oxidisation of the containment, Phosphate, ammonia or what ever, is achieves to over come the cyclical growth pattern of the algae which is to be killed off. It can take nearly 10 times the concentration of the contamination in ‘absolute chlorine’ to get ahead rather than just contributing to the Combined chlore levels, which will create more and different problems (trichloramine NCL3+ OH-).

Sometimes its necessary to us a Non chlorine oxidizer to break down the Nitrogenous compounds so that the chlorine can then do the sanitising work without these consequences. But they are not a commonly available compound - potassium peroxymonosulphate or permonosulphate is one of them. This will cause difficulties later on with chlorine levels as it will mask the chlorine like Active Oxygen products such as Reva. So you have to be careful and cannot just 'wing it' and throw them all in together. However unlike the others permonosulphate has a low pH near pH3 ,so there is a positive correction needed rather than the usual negative correction. The advantage of going this way is that there is unlikely to be any consequences for the liner or fittings, which can suffer under intensive chlorination.

So if you get a problem, which seems to be unshiftable, call for help rather than trying to get there with crude or untargeted remedies. Because if there results of repeated efforts are also part of the problem, that is elevated TDS, then there really will be no where to go but to refresh and start again- difficult to do when your forbidden to use the hose. So the expression 'penny wise, pound poor' was I think invented to describe pool ownership. Facing the prospect of maintaining a body of water in these difficult circumstances is trying on the patience but with help its possible to get through. If anyone is not yet reached the trouble time, then count your blessings as just when you think that its all simple and cannot understand what all the fuss is about, its then that your saga can begin.

This and other tombs are not meant to be poetic, nor heroic but rather informative, for recognising a problem in pool water quality is the first most important step to finding its remedy. And as has been extolled many times on this and other forums, there are few out the really understand what to do in challenging times. Most problems have simple solutions, but there are an increasing number, which do not, and it’s these that need special attention.

That is the message of this post.

Andrew