Problems With Trichlorisocynuric [Sp?] Acid 90% Granular

[jaideeguy]

I've been using another brand of trichlor, but this last time I bought a 50k tub of 'acuchlor 90' I've noticed not only that it doesn't last as long my old brand, but it sees to not totally clear the pool....leaving a slight milkiness that will turn green with algae in a couple of weeks, then I shock dose and add flocculant, vacuum to waste and looks good for a couple of weeks, then the same cycle again.....3 times now.

My uneducated suspicion is that maybe this new trichlor is leaving some fine sediment/residue behind and the algae is attaching it's self to it. I have been vigilant in testing and keeping my chlorine levels quite high and it has been quite hot this summer.

Any comments or suggestions??

[jbrain]

Do you test for free chlorine or only total chlorine ?

How are your alkaline and Ph readings ?

[jaideeguy]

sorry jbrain.....I posted last night but it doesn't show???

Anyway, I do the standard chlor [yellow] and PH test [red] and PH is neutral and chlor is way high due to my heavy dosing for my latest algae attack.

[tollgate]

If you are only using trichlor, maybe your cya level has gone way too high. Have you tested it?

[jbrain]

sorry jbrain.....I posted last night but it doesn't show???

Anyway, I do the standard chlor [yellow] and PH test [red] and PH is neutral and chlor is way high due to my heavy dosing for my latest algae attack.

With the standard test you only measure total chlorine and Ph, but it is the free chlorine that sanitizes your pool water.

Shocking is to no avail if you don't know the free and combined chlorine levels, because you must use the correct amount of chlorine otherwise you may make things worse.

You may have 10 ppm of total chlorine in your pool, if the combined chlorine level is too high the chlorine has no effect.

What you need is to find a decent test kit and take it from there. Guessing doesn't really work in pool maintenance.

Have a read here http://www.underwaterstuff.com/definitions.htm it will give you a better understanding about what you need to check for and how to shock .

[Bagwain]

Cynuric acid only works between 50-80 ppm.

Then chlorine lock can happen. Then algae problems!

You can get test kits that do test for cynuric acid.

[SantiSuk]

Cynuric acid only works between 50-80 ppm.

Then chlorine lock can happen. Then algae problems!

You can get test kits that do test for cynuric acid.

I posted somewhere back a learned article (not by me) that suggested that any level of Cyanauric above about 30 (I think it was) is wasteful.

Don't you just love the world of pools. So full of so many different opinions. I just wish someone would publish an authoritative guideline on pool chemistry that is based on acknowledged scientific research

Ah, found it now on my hard drive. Attached. The phrase that hit me was "The graph shows very little difference in stabilization from 25 to 100 ppm CA". Based on pool research in Phoenix too, which can't be that different from Thai climatic conditions.

Sorry for the hijack OP. I don't have a solution, but if I were in your position I would buy a 5kg tub of some other chlorine (which unfortunately is ridiculously expensive pro rata to a 50kg tub). Run with that and if your problem disappears you know that you bought cr@p chlorine. I was very happy with a 50kg tub of cheap Japanese chlorine I bought from a Do Home watsadu in Isaan.

The cheap good bulk chlorine is Japanese in origin - costs typically 5,000 baht for a 50kg tub. The really cheap stuff is Chinese at about 3,500 kg baht a tub. Maybe that's what you've got and maybe it's a false economy. That info is based on a chat I had with the Thai boss at Pool & Spa on KingKaew Road, Bangkok a year back. He claimed to be the biggest importer of chlorine in Thailand and looked to have a shed that backed that up! He talked some bollux too mind. You can't trust anyone's opinion on pool chemistry as the sources seem to be myth and custom and practice based.

Once you get into pool ownership a couple of years you start to get little issues. I found that's when I progressed from the cheap CL/pH kits to a digital tester to cover a few more tests every couple of weeks. I test for both free and total chlorine, pH, total alkalinity and CyA. The cheap kits still have their use in the testing cycle. I use one every 3 or 4 days and then every 10 days or so test the full range. Others will tell you that they have used the simple kits for 20 years and poo poo us testing junkies. That's pool life for you!Cyanauric acid and swimming pools.pdf

Edited August 28, 2013 by SantiSuk