My first algae bloom

[monoptn]

This morning I went out to check my pool and found it had a greenish tint and there was green dust around the bottom and sides in spots. The bottom of the pool was visible, but far from crystal clear. Nothing remarkable has occurred lately: not much rain, wind, debris in pool, no parties or heavy use, etc. I tested after finding the green tint and found FC at 7, ph at 7.7, alk at 40, CYA at 60, CC at zero...maybe .5 (I got a very very faint pink tint that went away with 1 drop).

After testing and scrubbing, I dropped the pH a little, added some baking soda to bring the Alk up a bit, and dumped in 256 oz of 10% bleach to get to slam level. I suspect I can knock it out pretty quick. I'm at FC 21 now.

But, what the heck could have caused this? I've been checking pH and FC a couple of times a week and they have been fine.....FC has never been absent, or even low. I don't bother logging the results of that normally. What might have caused this bloom?

 

[mknauss]

Are you brushing the pool every few days? Once swimming reduces, you need to brush more until the pool water cools down to where algae is not active. Otherwise, who knows, the system got a burst of organics or the FC dropped too low in an area and the algae bloomed.

 

[monoptn]

Are you brushing the pool every few days? Once swimming reduces, you need to brush more until the pool water cools down to where algae is not active. Otherwise, who knows, the system got a burst of organics or the FC dropped too low in an area and the algae bloomed.

Brushing occasionally in the area the robot does not reach, like behind the ladder, and in the seats. Is more regular brushing required, or would the robot normally be adequate? The robot runs about every other day, on average. Our pump runs 15 hours per day.

 

[mknauss]

Robot helps. Lots of areas the robot cannot reach. This is a typical thing we see every fall. Members report in the fall that as the pool gets less use and not ready to close or water temperatures still above 60F, algae becomes more prevalent. Might be what we describe above, could be less testing/maintenance of FC level, etc.

 

[monoptn]

Robot helps. Lots of areas the robot cannot reach. This is a typical thing we see every fall. Members report in the fall that as the pool gets less use and not ready to close or water temperatures still above 60F, algae becomes more prevalent. Might be what we describe above, could be less testing/maintenance of FC level, etc.

Ok, thanks! I will brush more regularly and may keep the FC up around 8-10 as well. I think I can knock this bloom out in a day or two.

 

[monoptn]

Robot helps. Lots of areas the robot cannot reach. This is a typical thing we see every fall. Members report in the fall that as the pool gets less use and not ready to close or water temperatures still above 60F, algae becomes more prevalent. Might be what we describe above, could be less testing/maintenance of FC level, etc.

This morning I had a little new algae, brushed it, ran the robot several times, brushed, a couple more times, kept at slam level all day I brushed again just now and don't see any green algae dust anywhere, just a haze to the water, visible in the deep end. Hopefully another day of SLAM, brushing, and robot action will clear it. I am running the pump 24-7. You think I'm close?

 

[red-beard]

Algae hides everywhere. I found algae in the plastic nuts of my old pool cleaner. It just needs a chance and it blooms. Lots of people find algae in the weir doors.

 

[monoptn]

The SLAM took care of it. After day 2, there was no more algae growth or settling of algae debris on the floor of the pool. I continued bushing and kept the chlorine level up, and after about 3-4 days the OCLT was zero loss. But the pool still had a slight haze to it. I could see the bottom , but it was blurry, almost like looking through a cataract would be. Not crystal clear. So, I kept the FC level up and kept the pump running, and kept brushing. Finally I decided to start dropping the chlorine level, and the pool began to get crystal clear again. Was it likely the high level of chlorine and perhaps out of whack pH levels that were keeping the pool hazy? Or was it the filter still pulling out dead algae? I am thinking I might could have dropped the FC a day or two earlier and the pool would have returned to clear when the FC dropped back to a sub-SLAM level. Thoughts?

 

[TexasBR]

All that chlorine will raise the pH

 

[monoptn]

All that chlorine will raise the pH

And high pH makes the water hazy, correct?

 

[duraleigh]

Or was it the filter still pulling out dead algae?

That's what it was......almost 99% positive. Hazy water has suspended particulate in it. When you filter out all the particulate, what you are left with is clear water.

Chlorine, once in the pool, has virtually no effect on pH and it does not make your water hazy......high pH or low pH.

 

[monoptn]

That's what it was......almost 99% positive. Hazy water has suspended particulate in it. When you filter out all the particulate, what you are left with is clear water.

Chlorine, once in the pool, has virtually no effect on pH and it does not make your water hazy......high pH or low pH.

Thanks for chiming in!