newbie help - white flakes on bottom of SWG pool?

[darin.brown]

first time with the pool this summer and noticed some small white flakes on the bottom/ledges of the pool near a return so I'm guessing they're coming from there. I do notice some white sandy-like stuff in the robot cleaner as well. A quick search looks like a combination of high TA/pH/CH might be the root cause but figured I'd post my full set of #s from the TF-100 for any other advice.

I did clean the SWG a few weeks back and saw some marginal scaling on the blades but haven't looked since. planning on that this evening.

I do know my CYA is on the low side and TA marginally high but everything else looks to be in line with recommended levels. We did get some chlorine pucks from the PB initially and I have plenty of those left over. Should I put some of those in a floater, turn down my % on the SWG to keep FC in line and see if that'll get the CYA to creep up? Apart from that, looks like cyanuric acid (stabilizer/conditioner) in a sock in front of a return?

pool is in full sun here in DFW so gather I want to get it up around 50-60?


FC - 4
TA - 90
pH - 7.8
CH - 350
CYA - 30-40

 

[pooldv]

You should change your location from Roanoke, which is in Virginia in my head, to DFW, TX. Yes, that is scale flakes from your SWG cell. Lower pH a bit and it will stop. That is your early sign that the CSI is creeping up. First the cell scales and then the pool will scale next. Keep your CSI between -0.3 and 0 to prevent scale in the cell and in the pool. I'm in the 6th season with my SWG cell and it has never needed to be cleaned. Yes, your pool will do better with TA 50-60. And you will want you CYA at 80 in the summer here.

More here, Pool School - Calcium Scaling

 

[needsajet]

Chances are that if you keep your calcite saturation index (CSI) between -0.3 and 0.0 that problem will go away. PoolMath calculates it for you after your numbers are all entered. pH has the greatest impact on CSI, and a slightly lower TA will also help.

Totally fine using up the pucks when CYA is low and pH is high, and especially because you know what you're doing! You can use PoolMath to know how much CYA added per puck, but you might find it slow. The pucks keep really well, so you can also save them for vacations and adjust with powdered CYA. I'm guessing your pool is algae free, so don't hesitate to go right up to 70 or 80 ppm CYA for your climate. The only reason not to is if you think you might need to SLAM, or if you'd like to leave headroom for using pucks in a floater while you're away.

Your numbers are already very close to being perfect, so I bet it won't take much at all to stop any scaling in the SWG.

 

[darin.brown]

thanks all.. the water itself is crystal clear thanks due in large part to this site. I'll drop the pH a bit as a first order of business and get some pucks going to raise the CYA some at the same time. looks like each puck will raise my CYA around 2ppm and poolmatch does have my CSI at around .2 so that backs up the feedback so far.

 

[pooldv]

Good plan, you've got it down pretty well.