About 2.5 weeks ago we had our concrete deck repaired and resurfaced. Once the concrete dust settled to the bottom, I vacuumed most of it out manually. I noticed some dark black specks that would move, but the vacuum wasn't able to pick up. I thought maybe they were tiny gnats or something and maybe my filter was overloaded, so I tossed in my robot vac to pick up whatever was left. I've left the pool to itself since and just cleaned out the skimmers as needed. I leave the pump running 24/7 as it does not greatly affect my electric bill and have a SWG. The weather had gotten colder the last couple of weeks, but this week has been abnormally high around 80F.
Yesterday I went out to vacuum out the leaves that sunk to the bottom, and now those little black dots are stuck on in many places in the shallow end. I scrubbed with the brush - no change. I tossed in some Vit C tablets but did not seem to make a difference. I didn't have many though and it was getting late. I'm not sure if this is algae or a metal stain? My water is clear.
Here are my results from yesterday:
FC: 6.6
pH: 7.5
TA: 90 (added a couple comes of acid last night)
CH: 60
Temp: 70F
Results after pool deck vacuuming (10/23):
FC: 4.8
pH: 7.8
TA: 90
Temp: 68F
Yesterday I went out to vacuum out the leaves that sunk to the bottom, and now those little black dots are stuck on in many places in the shallow end. I scrubbed with the brush - no change. I tossed in some Vit C tablets but did not seem to make a difference. I didn't have many though and it was getting late. I'm not sure if this is algae or a metal stain? My water is clear.
Here are my results from yesterday:
FC: 6.6
pH: 7.5
TA: 90 (added a couple comes of acid last night)
CH: 60
Temp: 70F
Results after pool deck vacuuming (10/23):
FC: 4.8
pH: 7.8
TA: 90
Temp: 68F
My initial thought was some metal, perhaps from rebar in the concrete, was cut and particles went into the water. But you said you tossed Vitamin C in there? Did you actually rub a Vitamin C tablet on a stain? It would be good to confirm for sure by physically rubbing the two.