White dust in pool when brushing

Gottabewet

Member
Jun 18, 2018
20
Hudson Vally NY
We just completed a 2 week slam for what may have been mustard algae. We were very active and monitored the pool hourly throughout this 2 weeks. It was a war and I felt we won. Pool was beautifully clear for 2 days. Now there is a clear/white dust that stirs up from plaster when brushing. Pool is clear and pretty 3 hours after brushing and vacuuming.

PH -7.3
CH 600 (prior to slam 450)
TA-120
CYA-70
FC-7
CC-0
CSI is -0.02

What could this be? What could make the calcium go up? Do we need to remove and replace some water?
 

Gottabewet

Member
Jun 18, 2018
20
Hudson Vally NY
No it is a 1 year old DiamondBrite plaster finished pool. The pool floor seems to have more clear/white dust come off when brushing. I rubbed my hand on both the floor and the walls and nothing came off in my hand. It's not a huge dust cloud but definitely noticeable.
 

JamesW

TFP Expert
Mar 2, 2011
16,595
Maybe dead algae or calcium carbonate.
Did you use any calcium hypochlorite?
Did the pH go high at any point?
What filter do you have?
If you have a sand filter, what does the backwash water look like?
If you have a cartridge or DE filter, you should open it and clean it well.
Brush daily, vacuum as needed and maintain good chemistry and the problem should go away.