60K gallon HOA pool - green algae on walls - CAT4000 system - CL kept at 3-4 - pH kept at 7.5. Tested daily with Palintest Kit. Also manage alkalinity and calcium. CYA kept around 50. When we ran into this problem we tested for phosphates and got them down to zero with Orenda PR10000. We treated a few weeks later with some Orenda CV-700. The algae problem persists. What is causing this algae and feeding it?? Thanks.
Where is it coming from!
- Thread starter ultimatt
- Start date
Welcome to TFP!
Short answer is you don’t have enough chlorine.
At 50ppm CYA, we recommend 4ppm as the lowest your chlorine should ever get, and 6-8ppm as the range you should try to stay in.
Short answer is you don’t have enough chlorine.
At 50ppm CYA, we recommend 4ppm as the lowest your chlorine should ever get, and 6-8ppm as the range you should try to stay in.
Insufficient chlorine allows algae to grow.
If you have algae, the chlorine is not being maintained at the correct level, period.
If you are a commercial pool subject to chlorine maximums, then you are in a difficult position.
If you are subject to maximums, then I would lower the CYA to 20 to 30 and then keep the FC as close to the maximum as possible without going over.
If you are subject to maximums, then I would lower the CYA to 20 to 30 and then keep the FC as close to the maximum as possible without going over.
Matt,
And... once you get algae, even an FC of 6-8 is not going to kill it.
You should take a look at our SLAM process...
Thanks,
Jim R.
And... once you get algae, even an FC of 6-8 is not going to kill it.
You should take a look at our SLAM process...
Thanks,
Jim R.
Since it is a “Public” or “Semi-Public” pool, you probably need to follow the local Health Department Rules and Regulations, which usually limit the FC to 5 ppm.
Some of you guessed correctly and we are subject to CL max of 7. We only have 12 days left in the swim season so I'm not going to shock it now (if i closed it for a day or two I would get roasted by the membership). However, I am going to take the CL to 6 to see if that helps. Thanks for all the good advice.
I wanted to ask one more question...for next season if we want to keep CL at 3-4 without algae problems where should we keep CYA? 30? We are going thru 220 gallons of 12% bleach as it is for the season. If I drop from 50-30 in the sunny south how much more bleach might I expect to use in the season? Thanks.
Confused about your desire to keep chlorine that low and trying to match CYA to that, especially in the south, where you can easily lose 4ppm daily (and that’s without actually using the pool).
Instead, get your CYA high enough to buffer your chlorine so you can keep a steady, safe level of FC and avoid any chance of algae. Not sure where in the south you are, but here in FL if I were using LC and not a SWCG, I would shoot for CYA of 40 or 50 and run my chlorine at or slightly above target range.
Instead, get your CYA high enough to buffer your chlorine so you can keep a steady, safe level of FC and avoid any chance of algae. Not sure where in the south you are, but here in FL if I were using LC and not a SWCG, I would shoot for CYA of 40 or 50 and run my chlorine at or slightly above target range.
- May 23, 2015
- 24,446
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It’s a public/semi-public pool. It has FC and CYA limitations imposed by the Health Department and, being public, there will inevitably some old grouch that will find out the FC is above 4ppm and accuse the operator of trying to kill everyone with “toxic chlorine levels”. There will be wailing and whining and calls for someone’s head to roll as well as threats of personal injury lawsuits (“the chlorine made my bunions worse and I was ordered by my doctor to stay in bed for 15 days to convalesce!!!”)
Not worth the pain …
Oh! Apologies, I missed that it was a public pool.
At least the chart is still helpful!