Fiberglass pool difficult to manage

[bplaxico]

Hi, I’ve had trouble with my pool since I joined this site. The last couple of years I’ve pretty much got it down. That was until yesterday. I left for work it was blue, came home to it green. A different green from years past posts. Very hard to scrub algae and other sediment off. I thought I noticed some new nicks on bottom, but it’s old. Yesterday, it seemed like there were many more. Anyway, brush is new has worked all season. Stats have been solid after SLAM. I got home late yesterday, so messing with it today.

FC 0.5
CC 0
pH 7.7
TA 65
CH 30 (reagent is old, ordered a new one)
CYA 30 (pretty normal for my pool)

Only difference in chemicals was FC dropped, I add bleach nightly according to Pool Math. I hadn’t tested CH since April, but it was 50. I know that’s low, but it’s fiberglass, maybe old fiberglass needs more. It’s just how all of the sudden it happened. I lowered pH to 7.2, and I’m slamming again. I’d be obliged if anyone has advice.

 

[Texas Splash]

I see a couple issues you need to address. First, with a FG pool from the '70s, it's very possible that shell had some calcium product added during the manufacturing process. So unlike those of us with today's FG pools, you do need to maintain a moderate amount of CH. I would recommend increasing the CH to about 200 for now to ensure the gelcoat shell doesn't try to erode.

As for the FC and algae, that's all about the SLAM Process which you are proactively doing now. I would be careful about a coupe of those readings and validate them once you get your new reagents. But focus on completing the SLAM for now (all 3 criteria), add some calcium, then come back and let know how things are going. After the SLAM, be sure to keep the FC balanced to the CYA as noted on the FC/CYA Levels. Hope that helps.

 

[bplaxico]

Sounds like a plan, thanks! FC was 10 last night and 9.5 this morning and looked much better. I think reagent is bad, it was near impossible to squeeze out of bottle. We had a bad cold snap, real bad a few months ago, and I think it's rearing it's aftermath on an old pool. Anyway, thanks, I'll update soon.