First Test Results

[PoolGuyNJ]

The shock level is 10X TC. He has no free cl. TC is 3
That will pretty much eliminate the combined chlorine and kill the organics.

Scott

 

[chem geek]

The 10x rule isn't correct when looking at TC (or CC) for reasons I won't get into here (see this post if interested). Nevertheless, this looks like it might be black algae (among other things; could just be dark green algae) and could use a good dose of shocking so a minimum of 16 ppm and could go up to the 24 ppm FC yellow/mustard algae level if you wanted to. As for how much FC it will take to get rid of the CC, that depends on what it is and if there is actually any ammonia in the water as well. I would just add a bunch of chlorine, then retest and add more if it drops until the chlorine gets up to the shock level.

Remember to read Defeating Algae in the Pool School since brushing the pool sides is part of the program to get the chlorine exposed to the algae to kill it.

 

[PoolGuyNJ]

I hadn't seen that thread. Hey ChemGeek, you are good. Butterfly and frustratedpoolmom, my apologies. I guess you didn't miss it. I may be good, ya'll are better. I won't be far behind as I am grateful and teachable.

Scott


Can't put my sig in now.

 

[Butterfly]

I hadn't seen that thread. Hey ChemGeek, you are good. Butterfly and frustratedpoolmom, my apologies. I guess you didn't miss it. I may be good, ya'll are better. I won't be far behind as I am grateful and teachable.

Scott


Can't put my sig in now.

Scott, no worries. We appreciate all your help!

Thank you for donating your time, knowledge and energies to helping folks.

Keep up the good work!

 

[Ray Mondo]

With TC @3 and FC @0, Its likely algae. TC is total chlorine and FC is free chlorine. Free chlorine does the work. With FC @0, there is nothing to kill the algae.

Ooops! Typing mistake. The FC and the TC were both 3 this morning. It was the CC that meant to put in as 0.

I have now edited the post.

Anyway, it sounds like 'Shock the Pool' is the next step.

A have been reading, and re-reading, the Pool School notes.

Thanks for the advice.

Cheers,

 

[JasonLion]

If CC is really zero, there isn't as clear a need to shock the pool. I would bring FC up to around 8 and hold it there for a couple of days, brushing the pool daily, and see what happens.

 

[Ray Mondo]

With your CYA of 40, your shock level is around 15 or 16 FC. See CYA/Chlorine chart in my sig and in Pool School.

OK, shock the pool is the plan so I have been hunting around supermarkets trying to find (inexpensive) chlorine so that I can increase the chlorine level to 15-16 as advised.

None of the supermarkets seem to sell granulated or powdered chlorine, only liquid.

I would appreciate some guidance about whether I am on the right track, and how to calculate the strength of the product so that I can figure out how much to use.

It looks like the best choice is a products that has the following details on the label:

Sodium Hypochlorite 4.2grams/litre
Avail Cl 4% m/v
Sodium Hydroxide 9grams/litre

That sounds like a pretty weak mix to me, but then it's only $1.76 per litre.

Thanks for the advice so far. All suggestions appreciated....

 

[polyvue]

That does seem a bit low... like one of the off-brand concoctions of bleach. It will work, but you may have to add considerably more and suffer the simulataneous addition of lye. I recommend trying to locate Clorox Regular Bleach; it specifies 6% sodium hypochlorite on the label. Also check prices of 10 or 12% liquid chlorine, commonly available in pool stores and larger hardware stores. The Pool Calculator allows you to enter the percentage of chlorine so your estimate of added chlorine for any given volume can be pretty close.

 

[frustratedpoolmom]

I see a company called Kleenco in Sidney sells liquid chlorine in large drums - perhaps you can purchase from them and have it shipped? I can't see on their website if they will ship it tho, it looks like a long drive for you... but maybe there are others, closer? If you have already tried this route, forgive me.

 

[Ray Mondo]

I see a company called Kleenco in Sidney sells liquid chlorine in large drums - perhaps you can purchase from them and have it shipped? I can't see on their website if they will ship it tho, it looks like a long drive for you... but maybe there are others, closer? If you have already tried this route, forgive me.

Thanks for that. So far I have been looking for local stuff. Sydney is 1000km away so freight might be a problem.

I might go for liquid chlorine from the local pool shop, at least to clean up the deposit on the walls.
Today I came across a new business, about to open in a couple of weeks, that describes itself as "bulk pet, garden and swimming pool supplies", so I'll keep an eye on that.

Cheers