How much does Dichlor and Trichlor affect CYA levels?

[tomfrh]

I have a tub of sodium dichlorisocyanurate (bunnings hyclor 3in1 brand). I've used it to boost chlorine levels here and there. Pool is SWG.

How much does it affect CYA levels? My CYA is already at 90-100.

Does the CYA keep accumlating, the way calcium can accumlaate if you use nothing but economy cholorine?

Also, what does "3 in 1" mean? Free Chlorine + Stabilizer (CYA) + ??



What about the trichlor? How does that perform? What's the difference compared to dichlor?


Thanks.

 

[mknauss]

See PoolMath for the effects on your CYA when using Trichlor or Dichlor.

NEVER use the '3 in 1" type products!! They typically have copper algaecide in them - and you do not want copper in your pool.

CYA builds the same as Calcium in a pool. So if your CYA is as high as you say, you should not be using anything but your SWCG or liquid chlorine.

Trichlor is in pucks/tablets and dissolves slowly, dichlor is in granules and dissolves quickly.

 

[tomfrh]

See PoolMath for the effects on your CYA when using Trichlor or Dichlor.

NEVER use the '3 in 1" type products!! They typically have copper algaecide in them - and you do not want copper in your pool.

CYA builds the same as Calcium in a pool. So if your CYA is as high as you say, you should not be using anything but your SWCG or liquid chlorine.

Trichlor is in pucks/tablets and dissolves slowly, dichlor is in granules and dissolves quickly.

Thanks. Yes I'd figured I should stop with the 3 in1. I just checked the poolmath. I didn't realise it raised CYA so quickly! Liquid chlorine it is.

What's bad about copper? All those green/orange algaecides seem to be copper based?

 

[mknauss]

Copper also builds up in the water. Normally the first sign of trouble is blonde hair that turns green or fingernails turning green. Shortly after you get staining on the plaster, and then the fun begins. Lots of chemicals to sequester the copper and remove the stains (maybe) and then draining and refilling.

So, no copper! (or silver, etc). No algaecides at all is best. No need if using TFPC.

 

[Donldson]

Also, what does "3 in 1" mean? Free Chlorine + Stabilizer (CYA) + ??

It's all a bit of marketing fluff, but generally a 3 in 1 chlorine product means oxidizer, sanitizer, algaecide. It can mean whatever they want it to mean though, there aren't really any laws (in the US at least, can't say for sure in Australia) that regulate such labeling. And as you see, Dichlor adds just about as much CYA to the pool as it does chlorine. Trichlor adds about 60%. 10 FC with dichlor adds 9 CYA, 10 FC with trichlor adds 6 CYA.

Copper is a good algaecide, which is why it is so widely used, but comes with some really unpleasant and costly side effects as Marty pointed out. Especially with a concrete pool you really want to avoid it. Maintaining proper FC levels in relation to your CYA negates the need for any algaecide, but a polyquat based one is preferable if one is needed or desired. With your CYA already so high and knowing copper is present I would consider doing a partial drain to bring both levels down. I don't know how high your copper level is (if no staining is evident then probably not too high yet) but lowering the level is never a bad thing.

 

[cfherrman]

With algaecides, how do you know the pool is clear of pathogens? Without a algaecide a clear pool is a sanitized pool.

Metals cause problems that cost more money, cannot do anything take a jug of bleach can't do why bother.

 

[tomfrh]

With algaecides, how do you know the pool is clear of pathogens? Without a algaecide a clear pool is a sanitized pool.

Metals cause problems that cost more money, cannot do anything take a jug of bleach can't do why bother.

Ok, thanks. Another useful bit of info from this site.

I was using algaecide for mustard algae, but in retrospect my FC and shock levels were just too weak and never killing the algae.

 

[cfherrman]

If you have algae, it is too late to use algaecides since they prevent algae from growing

While on the subject, phospates are a non issue with tfpc as well