Algae and warm weather

We are in Florida it's also hot here and if you make a mistake you will have green in a pool within days.  Anytime we see any algae issue you have to look for the factors related to the bloom, is it due to not enough chlorine being added the week before?  Does the pool have a leak and is it not holding chemicals? 

If you show up the next week and have a 5ppm chlorine reading and still have algae in a pool then there is a runtime and/or filtration issue and possibly high phosphates.  Recommend checking the filter really well and selling the customer a new filter if needed.  The runtime is just as important for proper turnover, here in Florida we use daylight hours as suggested runtimes.  I’d also make sure the customer isn’t messing with the settings or adding anything after you leave (happens a lot).

If it's happening a lot look for common denominators, is it one tech on only certain techs that are having this issue?  Have you gone out personally before a tech or after to do a quality control check to ensure everything was done properly?  We do not use any algaecides in our regular pool service and never have any issues in our pools.  Remember any time you use an algaecide it will also eat chlorine so you’ll need to add more to offset.    

These are just some things you can use to help narrow down issues.  Hope this helps! 

Free chlorine FC is the key to killing algae. So your 5 ppm is that a total chlorine TC reading or is it FC? All the TC reading is telling you is that there is 5 ppm chlorine but what form is that chlorine? It could be a majority of combined chlorine CC which is pretty useless when it comes to dealing with algae. If you want your weekly sanitizer to be effective against algae first you must ensure that your FC level is being maintained higher than the CC. Ideally you want 0 CC. Test TC and FC. Subtract FC from the TC and this is your CC. If the CC is higher than your FC algae will be a problem. You must initially get your FC to a 10x of the CC.  If CC shows higher than FC, I would first recommend a gradual drain and dilute. Start with draining and diluting 2’ feet then retest and see if the CC has gone down. Then add enough of a chlorine shock to increase the FC 10 x that of CC. So if your CC is 1 ppm add enough chlorine to reach 10 ppm of FC. After this you should test every week and always ensure that the FC is higher than the CC. Once you have lowered high levels of CC you can manage the build up of CC by proactively adding the proper amount of chlorine to keep the FC at a 10x over the CC. If you can do this you will not need algaecides. You also need to ensure that your FC is at LEAST 7.5% of your CYA reading. Which is why you need to keep CYA levels between 30 to 50 ppm. 30 ppm x 7.5% = 2.25 ppm FC.  50 x 7.5% = 3.75 ppm.  If using trichlor tablets then CYA will be high and this will cause interference to the HOCl killing agent of the chlorine and so your chlorine residual may not be enough to kill algae. This typically occurs in hot summer in pools that are dependent on trichlor. If your CYA is running high you should do what you can to lower it to between 30 to 50 ppm. Lastly brush any algae pool every day. Yep I said every day until the algae is gone. Chlorine, algaecide etc..can not distrupt algae in the way that brushing does. If a pool got algae on my route I went to that pool everyday and brushed it until the algae was gone.

Lots of good info here already. I have my guys shock the pool up to 30ppm, add at least 1 tab (if none left add 2, if not salt) and clean the filter (regardless of the last time it was cleaned). We include filter cleaning so that part might not be possible in some areas where you charge for it. Then the following week they should clean the filter again. I also tell them to check the run time but usually the runtime issue is indicated by a chlorine level above 0 but still showing green. 

This seems to work well for us in N Florida. Doesn’t mess with our operations too much and generally has a good result. 

I have not heard any good reviews of Pool Rx. but I also haven’t asked too many people. Doesn’t seem to be a big thing here, but I could be wrong. 

This is a very informative video and Fred did a great job. One caveat on discouraging pros from having to test or remove phosphates would be that high phosphates combined with high calcium levels can lead to the formation of calcium phosphate scale which can present a problem especially upon heat exchangers and salt water generator cells.  Also, if as Fred stated the minerals get consumed and micro algae can begin to feed again, phosphates would accelerate that process. Hopefully, someone would get the booster in before an outbreak occurred. However, its my viewpoint that discouraging a proper maintenance of phosphates is not your best selling point. The chelation and effectiveness are great selling points however.