Warm water presents ideal conditions for an algae ‘bloom’ and insufficient maintenance can result in a nasty, unhealthy green mess that takes the untutored days (or weeks) of hot, sweaty labour to clean up. Pollen levels fall off in high summer but airborne dust, carrying algae spores, is on the increase. Algae rapidly use up CO2 in the water, so pH rises and chlorine becomes less effective - allowing algae to flourish - which raises the pH…and so on.
At pH 8.6 the dissolved minerals come out of solution (water turns milky or dull) and the tiles, plumbing, steps and every grain of sand in the sand-filter become coated with lime-scale. In a matter of days the sandfilter can turn to solid stone and that often means a new filter. Lime-scale on the walls can only be removed effectively by draining the pool and acid washing. An algae bloom is an avoidable, expensive catastrophe. Avoid algae bloom by routine super-chlorination: the pool pros’ right hook and a regular event in some chlorinated public pools.
Super-chlorination - 50 cubic metre pool - (adjust chemical doses for your own pool-volume). Every fortnight trickle 2 litres of Sodium Hypochlorite (liquid chlorine, available from us) via the skimmers with the rotary valve set to ‘FILTER’ and the pump on. After 5 minutes, stop the pump and set the rotary valve to ‘RECIRCULATE’. Run the pump for 4 hours to circulate the liquid chlorine. After 1 hour add 1 litre of hydrochloric acid (or 500g of pH-minus), to the pool at the Jets. Don’t use the pool for 12-18 hours after super-chlorination; do it at sunset so you can swim the following afternoon. (Can you remember being puzzled as to why the Municipal pool was closed on a hot Wednesday morning in the school holidays? That’s because they had superchlorinated the night before.)
In addition to the regular fortnightly treatments, super-chlorinate after a thunderstorm, dust-storm or if the pool is subjected to unusually heavy pollution such as a child having an ‘accident’ in the water. If your pool turns from a Deep Blue Dream to a Dark Green Nightmare overnight here’s how to help yourself if you have a 50 cu metre pool (before calling us to the rescue!).
As soon as you can see or feel algae, superchlorinate as above. Then pulverise 2 chlorine tablets in a plastic bag and put the powder in the skimmer basket. These 2 actions will kill the algae, turn it brown and prevent it from upsetting the pH too much. Add a half-litre of hydrochloric acid if pH has started to drift above the optimum of 7.4. (Remember to adjust chemical doses for your pool-volume). Now wash your hands.
Thoroughly scrub the sides and bottom, turn the pump off and apply flocculant. Mix flocculant in a watering can and distribute it evenly over the pool surface. Allow the water to remain still for 12 hours and then vacuum the settled sediments to ’WASTE’. Breathe a sigh of relief and consider yourself told off! Check the water chemistry daily and add chemicals little and often for best results. Pools can go bad really quickly in summer, so take our Pool School course and you will never need to take the remedial action above.
Please contact Deep Blue Pools for more information - 952 594 393
www.deep-blue-pools.com
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Pool Care 
