Super shocking for black algae, whats the final answer on swimming while you shock?

[rtilghman]

I'm currently super shocking my pool, meaning I've been maintaining my FC around 30ppm for the last few days in an attempt to eradicate some annoying black algae that's been taking off in the horizontal grout under the waterline (I have glass tile on ledges and steps, and for some reason the black algae really likes it).

Anyway, the question I have is how safe is it to swim in a pool running 30ppm FC? I've gone in myself to abrasively sand and grind the remaining algae on the grout, but I try to limit my time in the water, and I'm more concerned with my kids... it doesn't seem to do me any harm, but at 40+ I've got so many issues who would know.

And yes, I realize there are a lot of posts that ask this question and Pool School speaks to it, but there's no really clear "at this level you should definitely not swim in it" type table to refer to.

Thanks!
Rick

 

[jblizzle]

What is super shocking?
What is your CYA?

We recommend following the SLAM Process process.
Have you read: Pool School - Black Algae

The safe FC levels are a function of your CYA. There is no hard a fast line. We recommend allowing swimming at FC up to the shock level for your CYA in the [FC/CYA][/FC/CYA]. But, above that your skin is not going to immediately fall off either.

 

[BasicTek]

It all depends on your CYA (see chart). If your CYA is 70 or higher then it's safe to get in but if it's under 70 then your FC is too high and could cause problems.

Now on the other hand if your CYA is 90 or above your "super shock" may not kill the algae. To defeat algae you need to SLAM and to do that you need a good test kit. How are you testing?

 

[rtilghman]

It all depends on your CYA (see chart). If your CYA is 70 or higher then it's safe to get in but if it's under 70 then your FC is too high and could cause problems.

Now on the other hand if your CYA is 90 or above your "super shock" may not kill the algae. To defeat algae you need to SLAM and to do that you need a good test kit. How are you testing?

Thanks for the replies guys. First, normal shocking as described by just about every pool resource I've read is running 10-15 PPM. Super shock is boosting to 30 ppm. Call it the difference between a regular preventative/cleaning shock and a "my $#%@ is $#&@ed up and I need to nuke it."

I live in central Texas, where my pool regularly gets up or even over 90f during the summer, and we never close our pools (meaning CYA is a serious mgmt challenge). In my experience when you've got a black algae or aggressive green algae bloom regular shocking (10-15ppm) doesn't address the problem, regardless of what your CYA is.

As for my CYA, it was up over 100 in February. However, I've found if I switch to Hypo for a period of time the CYA breaks down. Basically comes out to about 10ppm in the summer per month. So, 6-7 months later I'm down around 60 or so. PH is around 7.4, generally keep my alka in the 100 range. Black algae is definitely dying, though after an initial big kill off the roots and vestiges are taking a LONG time to kill... I'm finding the deeper the algae the less responsive it seems to be to the Hypo. Not sure why that is... maybe the chlorine isn't working down deep as well as it should? Or maybe my jets need some alignment...

So, it sounds like we shouldn't swim.

Best,
Rick

 

[BasicTek]

At TFP they don't just shock they SLAM, and I've seen it work every time but it's very dependent on a proper test kit. Most resources do not take in account the FC/CYA relationship, and most test kits are inadequate to perform a SLAM. Follow Jason's advice above, and get a proper test kit you will not believe how much easier (and cheaper) it is to manage your pool

 

[rtilghman]

Oh, clearly I'm following SLAM since, as I mentioned, I've been running my pool constantly at 30ppm Chlorine for multiple days now... Testing about 3-4 times a day with a full Taylor kit, so I'm pretty solid on the accuracy of my results.

At this point I'm basically holding steady on the Chlorine, but as I mentioned the "black algae staining" from the roots is really proving a PITA. I crawled in with a plastic sanding pad and a hand held grout scraper to try to break it up a bit, but the fact that it's grout between glass tiles reduces my options... not really interested in ruining my glass tile with an aluminum brush, so my options for getting into those roots is limited.

-rt

 

[BasicTek]

which taylor kit?

How are you chlorinating (liquid, pucks, powder (only cal hypo))?

CYA doesn't usually break down very fast unless you are replacing a lot of water, if you are only adding chlorine that doesn't have CYA (hypo liquid bleach etc). Do you know what it is now?

SLAM requires 3 criteria to be met or you just raised your chlorine for a while,

pass overnight chlorine test
cc less than .05
water crystal clear and no visible algae

the FC should be raised based on the chart not 30 unless your CYA is 80. There are additional steps for black algae that Jason referenced

 

[HiddenRiver]

Oh, clearly I'm following SLAM since, as I mentioned, I've been running my pool constantly at 30ppm Chlorine for multiple days now... Testing about 3-4 times a day with a full Taylor kit, so I'm pretty solid on the accuracy of my results.

At this point I'm basically holding steady on the Chlorine, but as I mentioned the "black algae staining" from the roots is really proving a PITA. I crawled in with a plastic sanding pad and a hand held grout scraper to try to break it up a bit, but the fact that it's grout between glass tiles reduces my options... not really interested in ruining my glass tile with an aluminum brush, so my options for getting into those roots is limited.

-rt

rtilgman -- we had an early bout with black algae right after getting my coping and tile redone and plaster patched. It hurt to have to brush hard with that metal brush on new plaster, but it worked and seems there are not many options. How about a bathroom tile brush people use in the shower to clean the grout? Good luck!