Algae an borates

[cschnurr]

I vaccumed the pool with the SWG on 100% for the entire day on Sunday.
I kept the pool at 20ppm on Sunday.

Sunday night, I turned the SWG off so I could monitor Cl consumption.
Sunday night 20ppm, Monday am 20ppm
Monday night 15ppm, Tuesday am 15ppm
Tuesday night 11ppm, Wednesday am (didn't measure)
Wednesday 7:00 (tonight) 8ppm.
Barely 50% drop over 3 days, I'd expect this consumption without algae.
SWG off the entire time. Weather was cooler High mid 70s and mostly sunny.

When I came home from work Wednesday, the water looked pretty clear from the back door, (Saturday before shock, it had a greenish tinge). But when I got closer, there were large deposits on the bottom of my pool (and a dead frog and mouse in the skimmer). I would have thought the deposits were algae, but is it possible it was dead algae?

I vacuumed the deposits to waste. The water looks pretty clear, I can read the 1/4" print on my vacuum in the deep end, no sign at all of any greenish tinge.

I test with a Taylor K2005 kit
FC 8-9ppm (measured twice: dilution 2:1 and 3:1)
CC (slight colour change but barely discernible)x3?
pH 7.6
TA 120
CH 280
CYA 80 (measured a week ago, but ran out of reagants)

As a sanity check, I also used test strips which are consistent with my measurements.

This may be totally unrelated, but last year I had a water bubble behind my liner in early August, and had an agae problem at the same time. There was no water behind the liner when I opened this year, but the water bubble is back again now and I have algae.


Any advice?

[cschnurr]

Wedneday night Cl measured 9ppm,
Thursday am still at 9ppm, with no sign of any deposits anywhere.

I'm thinking I'm either fighting pollen (as mentioned on other threads) or am on the brink of algae blooming below 8ppm.

I know this is not in line with POP, but I've hosting neighbourhood party coming on Sunday. Since whatever the deposits were are gone, and didn' seem to consume my Cl, I'm thinking I'll maintain Cl around 10ppm for the weekend, after Sunday let it drop to my 'normal' value around 5. If algae blooms I'll shock then.

[aylad]

Your plan sounds good to me...if you're holding chlorine overnight and have no abnormal consumption during the day, and if your water is back to blue, I would just hold the Cl a little high until your party is over, and shock afterward just to kill any remaining "nasties". I think the film that you originally found on the bottom and sides was residual live algae, which can be present with no CC reading or huge drop in chlorine. I also think that since the film disappeared and the deposits appeared after an extended shock, that you probably had deposits of dead algae on the bottom and correctly vaccuumed them to waste.

I strongly suspect that you're either fighting pollen (don't remember offhand where you are but we're fighting an ongoing battle with it in Louisiana this summr), or possibly some sand blowback from your filter. Is there any other way that dirt might be introduced into the pool? Usually when the deposits start showing up in the same places, especially if they are near the return jets, it's more a matter of dirt or pollen that is settling there due to water movement. Algae usually deposits itself a little more randomly, and takes up larger spaces.

Janet