We also have been battling black algae for about 4 weeks. It started as a few linear blackish streaks in the bottom of the pool and progressed in getting wider and longer, and then patches of black showed up on the plaster walls. During the late winter early spring we had a tile guy replace the ceramic tiles, but he also patched the plaster in some locations. He cleaned when he was done and I suspect the algae was on his brushes...next time all brushes will be sanitized! We have been using combinations of solid granules of Refresh Calcium Hypochlorite and bottles of chlorine brushing, adding more chlorine, from time to time adding algicide. At night and in the morning I could get the FC level up to 20, but by mid morning to noon the levels were down to 0.5. This past week we double whammied with 3 gallons of chlorox and trichlor pills in the bottom and five pills in the skimmer and then 8 one pound bags of calcium hypochlorite. This morning the FC level was around 20 and this afternoon 15, and this evening 8. I am wondering, if the level is still high, should we consider the job complete or should we zap it again tonight? Still see a shadows on the walls where the algae
was. Will stains remain where the dead algae was located?
mod note: merged two threads with same discussion, post 1 above and post 2 below.
We are new to TFP but this is our second season with a pool. Last year we opened the pool and had no problems with algae, just with getting the DE filter clean and changed after three years of non-use (previous owners--this pool is probably 25 years old). All the chemistry was easy. This winter we had ceramic tile work done and we had to refill our pool (with well water) and then began the process of testing and adding various chemicals, all very uneventful. Several long, thin black streaks showed up on the bottom of our pool. We ignored it, and kept adding the chemicals to keep our pool clean and clear, also used our robotic brushing machine daily. We turned the DE filter off at night. The streak grew and then dark blotches began to show on our pool walls even with the robot brushing. We discovered then it was likely black algae. We started shocking the pool at night using chemicals from the pool store, then switched completely to liquid chlorine bleach, but still in the daytime the FC levels would go down and we did not know that we needed to keep them high all day and all night. We added algicide, we added Refresh (Ca Hyochlorite) and bottles of chlorox and recently i added 4-5 chlorine "pills" to the bottom and another 5 or so to the skimmer. For 5-6 nights in a row we have scrubbed with a wire brush, increased the chlorine levels to 20+ and some nights added CuBromide and some nights Na Bromide. The pool store had varying directions but one very young lady was the one who told us we could not let the levels go down during the day. So the past three days they have gone down to 1, but after last evening's 8, one pound packets and 2 gallons of concentrated chlorox we finally got the FC levels to stay at 20 this morning, 15 around 5:30 PM and 8 at around 9:30 this evening. I still see a shadow where the algae was on the walls but the pool floor is clean, steps too. Is this a stain left behind or more algae? With these maintained high FC levels can we let up tonight or should we keep adding chlorine and brushing again? The filter has run 24/7 for about six days. I am very concerned that our gunnite/plaster will be damaged too from all the brushing.
I am about ready to get the dump truck of dirt in to make the pool go away.
was. Will stains remain where the dead algae was located?
mod note: merged two threads with same discussion, post 1 above and post 2 below.
We are new to TFP but this is our second season with a pool. Last year we opened the pool and had no problems with algae, just with getting the DE filter clean and changed after three years of non-use (previous owners--this pool is probably 25 years old). All the chemistry was easy. This winter we had ceramic tile work done and we had to refill our pool (with well water) and then began the process of testing and adding various chemicals, all very uneventful. Several long, thin black streaks showed up on the bottom of our pool. We ignored it, and kept adding the chemicals to keep our pool clean and clear, also used our robotic brushing machine daily. We turned the DE filter off at night. The streak grew and then dark blotches began to show on our pool walls even with the robot brushing. We discovered then it was likely black algae. We started shocking the pool at night using chemicals from the pool store, then switched completely to liquid chlorine bleach, but still in the daytime the FC levels would go down and we did not know that we needed to keep them high all day and all night. We added algicide, we added Refresh (Ca Hyochlorite) and bottles of chlorox and recently i added 4-5 chlorine "pills" to the bottom and another 5 or so to the skimmer. For 5-6 nights in a row we have scrubbed with a wire brush, increased the chlorine levels to 20+ and some nights added CuBromide and some nights Na Bromide. The pool store had varying directions but one very young lady was the one who told us we could not let the levels go down during the day. So the past three days they have gone down to 1, but after last evening's 8, one pound packets and 2 gallons of concentrated chlorox we finally got the FC levels to stay at 20 this morning, 15 around 5:30 PM and 8 at around 9:30 this evening. I still see a shadow where the algae was on the walls but the pool floor is clean, steps too. Is this a stain left behind or more algae? With these maintained high FC levels can we let up tonight or should we keep adding chlorine and brushing again? The filter has run 24/7 for about six days. I am very concerned that our gunnite/plaster will be damaged too from all the brushing.
I am about ready to get the dump truck of dirt in to make the pool go away.