Cannot maintain FC levels w/ BBB

[Slachey]

Thanks PoolDoc.

Last night I took the FC level to 34 at 8:30pm (sunset). At 6am (sunrise) the FC was at 29 (loss of 5 ppm overnight). And at 1pm the FC was 21. I am leaving for 3 days and am very concerned about not having enough chlorine in the pool to last even if I take it to ~ 30.

Watermom said that she would never take a vinyl pool to 39, so I would like to know what is the level I should take it to before I leave, knowing the losses I have been experiencing?

As an FYI, over the last 3 days the pool has been clear and there has been no greenish spots, and the CC is close to 0.

This is getting very frustrating, as I really want this to work, but I cannot see myself continuing to dump gallon after gallon of bleach in this pool everyday. Any further assistance would be appreciated.

Thanks!

[PoolDoc]

Cleaning up is much harder than running a cleaned up pool.

A *SINGLE* episode of algae will often consume more than a month's worth of chlorine! And, mustard algae is the worst. Plus, for unknown reasons, some pools tend to have recurrent episodes of mustard algae.

The fact that you lost 5 ppm overnight strongly suggests that something is still going wrong in your pool. You need to continue raising the chlorine overnight, till the overnight loss is closer to 1 ppm.

Regarding liners, there's no particular answer. Liners vary greatly in susceptibility to bleaching, even within a single manufacturer's product line, and the details that would allow you to predict which is which are generally known only to the companies printing the vinyl sheet stock -- which are NOT the same as the companies making the liner.

The mustard algae guide is here: http://pool9.net/mustard .

And . . .

Anyhow, if you would, fill out these two forms, so we can be more confident we're not overlooking something:
http://pool9.net/pf-equip-form/
http://pool9.net/pf-hist-form/

[Slachey]

Thanks Ben.

I will stick with this method and will fill out the chart when I can. I have had a crazy couple of weeks.

Back to my current situation. How high do you think I should take my FC today, knowing that I will be gone for 3 days?

[PoolDoc]

That's why I was asking for the that info -- so I could advise you better.

Probably your best bet is to keep boosting to near 30 ppm, and hope it's under control when you leave. If you want to take an additional step, borates over 60 ppm permanently inhibit algae, although it's not as effective against mustard algae.

You don't really have time to lower phosphates, if you are leaving this week. That requires that you have sufficient phosphate remover AND can test accurately. It's useless to lower PO4 levels from 2 ppm to 0.5 ppm (500 ppb): it only begins to be effective as you go below 0.2 ppm. The target is 0.1 ppm or less.

But you can raise borates quickly with boric acid: just dump the correct amount (or more) in. Some small pH adjustments may be needed after.

I just finished a dosing guide: http://pool9.net/chart/vacation-dose/ ; there are links to the products in the chart.

[Slachey]

PoolDoc,

So I took your advice and increased my FC to ~ 34 ppm before I left on a short vacation on 7/2. During my vacation I had someone come over on 7/3 and add 3 jugs of bleach to keep the FC high while I was gone. I was not sure what the FC was during this time, but on 7/4 when I came home the FC was 22. Fast-forward to last night at 8:40 pm (a little past sunset) my FC was at 11.2. When I awoke and tested at 5:30am the FC tested at 12??? This was a bit odd, but after I returned at 11am and tested again the FC was at 11.0. I added a 121oz jug of 8.25% bleach at this time as I was not sure if things were completely cleared. I just tested at 8pm (a little prior to sunset) and the FC was 12.4.
.
I don't want to get excited just yet, but I think that I may be on the right track here as the bleach consumption has gone down dramatically.

I'll keep you informed as to my progress.

Thanks again for all your patience!

Slachey

[PoolDoc]

Unfortunately, mustard algae tends to be persistent. Brush the pool as thoroughly and carefully as you can. The goal is to scratch off the slime that protects tiny algae pockets and expose them to chlorine.