Is a little algae to be expected?

kathy58

Bronze Supporter
Jul 22, 2019
12
southern maryland
Using our Taylor K-2006 Test kit and testing the water every morning, we have had wonderful crystal clear water! Our cya is 45, so the desired chlorine range per pool math is 4-8ppm. We have never been below 4, and I use the pool math calculations to maintain it at 7. I brush and vacuum the pool at least once a week. On the 3rd or 4th day after brushing or vacuuming, I will notice a slight greenish covering on the sides and bottom, but only in a few places - not the entire pool. I brush that away, little green clouds form but quickly dissipate - the water still remains very clear. Is this algae I am brushing away? Is that to be expected? We have an 18,000 gallon inground vinyl liner pool, and it has been very sunny, hot and humid here in Maryland. Our 14th day of 90+ temps. My chlorine test readings are pretty consistent each morning at 4.5ppm, dropping from the desired 7 after 24 hours. I've occasionally checked our overnight loss, and it is 1ppm or less. Should I be concerned I've got an algae problem and perform a SLAM? or is a little algae to be expected, and keeping the chlorine levels within the suggested range is all that is needed to take care of that little bit? Thanks for your time! Kathy
 

markayash

Gold Supporter
Mar 21, 2016
2,766
Atlanta Ga
Will let the experts chime in but a little algae isn't good..My SWG wasn't keeping up ( FC dropped to 1 and I thought the SWG had died ) and I was also seeing a few green spots that brushed off but came back.
After a 3 day slam it got rid of it and I even had to turn the SWG down.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
It is true that if what you are seeing is algae, and it sounds like it, that's never good. Whenever we see it, we SLAM it using the SLAM Process page. The fact your water hasn't gotten cloudy yet is good for you in that you might catch this thing quickly. But regardless of the heat, and we are HOT in Texas right now, there should never be algae. I'd start the SLAM Process right away in hopes that you eradicate the green as soon as possible. If you have any questions or problems along the way, let us know. Good luck!
 
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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
That is hard for us to tell in all cases. Your area sees pollen blooms later than us down here, but I would guess most of that is gone by now. Plus, with pollen you should see it on cars and everything else. Dirt sometimes gets blown into the water, but you should be able to collect that. When you brush something that looks green and just disappears into a plume in the water, that's generally a sign of algae. Do you have any areas of the pool where a small algae patch could be hiding? Behind a light, hollow steps or a ladder?
 

Texas Splash

Mod Squad
TFP Expert
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Here's something else you can try. Try to pinch what you are seeing between your thumb and forefinger. That should be easy to do if it's sand, harder but possible if it's dirt.......and impossible to do if it's dead algae Besides the clouds pushed-up when brushing, the stuff can appear along the crevices and divots on the pool floor because it can escape out of the pool current and settled in those low places. In both cases - SLAM!
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
We do have a ladder - I will invest in a smaller hand brush to make sure that is totally cleaned. What are hollow steps?
Some people have those wedding cake step in the pool (hollow) that hide algae. If you can remove the ladder, I would do that. Ladder rails, poles, and even the steps themselves can hide algae. If you are able to open any of it and inspect that's ideal. Some people also use a turkey baster to inject some chlorine into those hard to reach areas, let it sit for a bit, then rinse it out.
 

kellyfair

Gold Supporter
Bronze Supporter
Jun 29, 2016
3,086
Tampa, FL
No, algae isn’t to be expected. I suspect your CYA measurement isn’t right, and therefore your chlorine measurement has been too low. If your CYA dot disappears between 40 and 50, you should round up to 50, and I would use 8 FC as target. After heavy use, test and bump it again.

Use 20 FC as your target during SLAM, and I use a kitchen brush to hit all the narrow spots and crevices on my stairs.
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
12,719
Houston, Texas
I would suspect the circulation is not good, and that you have dead spots where the chlorine isn't reaching. You can get a few ping pong balls and toss them in the pool while it is running and see how they move in the pool. The ping pong balls should be able to float around the edge of the pool until they reach the skimmer. If they don't follow the edge of the pool or bunch up someplace then you need to adjust the return jets so there is good flow around the pool.
 

kathy58

Bronze Supporter
Jul 22, 2019
12
southern maryland
Our pool is a rectangle, and yes the algae spots are primarily along the walls in the deep end when I see it. Thanks for the ping pong ball idea - I will try that now to gauge our water circulation. I will round up the cya measurement too - it was right between 40 and 50, but rounding up to 50 makes sense. Thanks all of the support!
 

JimMarshall

Gold Supporter
TFP Guide
Jun 5, 2017
1,003
Oil City PA
I would suspect the circulation is not good, and that you have dead spots where the chlorine isn't reaching. You can get a few ping pong balls and toss them in the pool while it is running and see how they move in the pool. The ping pong balls should be able to float around the edge of the pool until they reach the skimmer. If they don't follow the edge of the pool or bunch up someplace then you need to adjust the return jets so there is good flow around the pool.
This is what I was getting at as well.

Our pool is a rectangle, and yes the algae spots are primarily along the walls in the deep end when I see it. Thanks for the ping pong ball idea - I will try that now to gauge our water circulation. I will round up the cya measurement too - it was right between 40 and 50, but rounding up to 50 makes sense. Thanks all of the support!
Kathy,

perhaps consider taking your next chlorine sample from one of the areas where the algae forms in addition to the area where you usually draw your sample and see if there is a significant discrepancy.
 
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