Trichlor Vs. Dual Action Vs. Triple Action Cl Tabs?

[IPvFletch]

I have one of those Rainbow Trichlor feeders in my system. It holds 12 CL tabs and keeps my CL levels just right.

While I realize "stabilized tabs" add CYA, I'm monitoring those levels and will take action when necessary (either drain some water out or stop and go back to liquid bleach).

In any event, my Question is which Tabs to get?

I was told "Trichlor" but when I go to Home Depot all I find is HTH branded Dual Action (orange lid) and Triple Action (yellow lid) tabs.

I've been getting the orange-lid Dual Action tabs and have used them for the past ~12 months without any issues. But are those the right ones?

I was almost wondering if Dual Action meant Dichlor and Triple Action meant Trichlor, in which case I have been using Dichlor w/out knowing it (whoops!) but I'm not sure that is 100% accurate. I'm also not sure that would be such a bad thing.. ??

Any ideas on this???

[chem geek]

As shown here, HTH Dual Action chlorine tablets are Trichlor with copper sulfate (and aluminum sulfate) in them. Continued use can build up copper in the pool and that can lead to staining and give blond hair a greenish tint. Be careful with this. I think you should use regular Trichlor tabs without the extra ingredients.

The Triple Action aren't HTH Duration (3-in-1) Chlorinating Tablets, are they? If so , then these are Cal-Hypo and should NOT be put into the same chlorinator as used with Trichlor or else a severe chemical reaction can occur.

Please read the ingredients listed on what you are using. I suggest that if you want to use Trichlor, that you use a pure Trichlor product and not one with copper in it. To prevent algae growth, either maintain a Free Chlorine (FC) level that is at least 7.5% of the Cyanuric Acid (CYA) level or use a supplemental algaecide (e.g. PolyQuat 60 weekly) or a phosphate remover -- even 50 ppm Borates would help.

[IPvFletch]

Woah, ok glad I asked!

I've used about 200 tabs of the Orange Lid (Dual Action w/Copper Sulfate) now for ~1.5 years. No staining yet, but I will STOP USING IT RIGHT NOW (glad I just ran out).

The HTH Triple Action (Yellow lid) is indeed 68% Cal-Hypo.

Is this better than Trichlor or do you think it contains the Copper as well (I don't have any on hand to look)? It only yields 46% available FC so it sounds kind of weak.

I understand about not mixing Cal-Hypo and CL directly together in a feeder/skimmer.

Otherwise, I will plan on using true Trichlor if I can find it (pool supply store? *gulp*) and will return the Orange Lid Dual Action which I just bought as a refill, and I just now checked, and it DOES contain Copper Sulfate (1.5%) and Other intert ingredients (5%). It yields 84% FC though which is nice.

So where to look for pure Trichlor??

Thanks!!

[chem geek]

The only thing that the % Available Chlorine means is the weight % of chlorine in the product -- it has NOTHING to do with its strength in the water which is SOLELY a function of the Free Chlorine (FC) level relative to the Cyanuric Acid (CYA) level. If you use only Trichlor, then you will build up CYA making chlorine less effective. This is why Arch Chemicals that makes the HTH brand adds copper to the copper to help control algae growth. The only problem is that it can build up too much copper unless you have sufficient water dilution.

If you use chlorinating liquid or 6% unscented bleach as your primary source of chlorine, then you will build up neither CYA nor Calcium Hardness (CH). If you want to continue to use Trichlor, you may need to use an algaecide (PolyQuat 60 weekly) or a phosphate remover. Cal-Hypo increases CH. The chemical rules of fact are as follows:

For every 10 ppm FC added by Trichlor, it also increases CYA by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases CH by 7 ppm.

Read the Pool School for more info.

[IPvFletch]

Thanks for the info Check Geek.

I do understand how CYA affects FC and I do understand that Trichlor adds a lot of CYA and I may need to drain my pool in a few years to get rid of some of that build up (it would also get rid of the copper build up, no?).

So you are saying Arch/HTH has added Copper so that it does not need to have as much FC (which is adding the CYA because it is stabilized CL)? So their take on Copper is that it will help reduce the amount of CYA but Copper then has it's own side effects anyways, so what do they really buy?

I've been using Trichlor Dual Action HTH (with Copper sulfate) tabs for 1.5 years now. My pool has never had an algae outbreak, although I've seen some build near my scupper when I forget to check the tabs (they last ~2-3 weeks). My pool is sparkling clean right now, but I'm beginning to worry about Phosphate levels now as you indicated. I've not had to EVER use any algaecide or shock or anything else (just the Trichlor tabs).

If you think my Phostphates are building - how can I go about testing them? I have the big custom TFP-1000 kit from (I think it is your designed kit?) the online store posted here.

I get the Polyquat 60 weekly - you are saying to substitute Trichlor with that to avoid CYA/CH build-up, right?

[chem geek]

Even if your chlorine usage were a low 1 ppm FC per day, then using Trichlor as your only source of chlorine would have the CYA rise by more than 100 ppm in 6 months if there were no dilution. Going 3 years before a drain/refill may not be frequent enough -- a partial drain/refill earlier may be required.

The purpose of the copper in the product you have been using is to prevent algae growth since continued use of the product increaes the CYA level making the chlorine less effective. So if you stop using this product and instead use more pure Trichlor, then your risk of getting algae is higher since you won't have the copper to inhibit algae growth (this is probably why you haven't had a problem using this product). On the other hand, your risk of staining from copper will go away. If you want to use pure Trichlor tabs, then use either a weekly PolyQuat 60 algaecide to prevent algae growth or use a phosphate remover including periodic testing and maintenance doses.

You could keep using the Trichlor puck with copper and use the K-1730 to monitor copper levels and definitely make sure your pH doesn't get too high since that is mostly what causes metal staining. If you go with the pure Trichlor approach, then if you use a phosphate remover you can use the Taylor K-1106 to test for phosphate levels. I have nothing to do with the TF100 test kit.

Of course, you could just use chlorinating liquid or 6% unscented bleach and not need any other additional products -- no algaecides, no phopshate remover, no pH Up since your pH will be more stable (you'll use a little Muriatic Acid every so often), but this approach requires more diligence since chlorine must usually be added every day or two unless you have a pool cover in which case you can usually add it twice a week.

Richard