CYA going up way too fast on puck pools

[Hilton]

I have a couple of pools that operate solely on chlorine pucks. My problem is that so many pucks are needed to keep the FC levels maintained in these pools that the CYA level jumps much too quickly. During a typical week we might use as many as 15 pucks (3 kilograms of pucks) to keep the FC level in the 2-4 range. In less than two months, my CYA levels are now at 60 - with two months to go. These are pools that fall under the definition of commercial by the public health act here, and have to be maintained according to that regulation...as such, I am limited to a legal CYA range of 30 to 80.

I currently use BioGuard Basic Tabs (formerly known as Tabguard Tabs), which are a standard 200g 100% trichlor puck. To my knowledge there are no "safe to use" puck products that lack cyanuric acid, or at least have less of it ... ? Near as I can tell, the people before me used ProEI and other typical 200g pucks, simply loading up the feeder with no regard for FC (their test kits only went to 5 and the log says 5 every day!) or CYA (rarely or never tested according to their logs).

These are massive pools (somewhere in the 180,000L to 350,000L range, I'm trying to figure that out right now), one of which takes about 10 days to fill with the available water supply, so I don't want to dump and refill if I don't have to. Last year I "held out" by adding 20% liquid chlorine on a daily basis from July to September, as it was the cheapest option, adding pucks only for the weekends when volunteers are watching the pool. This year I've started adding 60% or 70% calcium hypochlorite, since the pools needed a little more calcium anyway, and will be ordering liquid chlorine soon if I can't figure something else out.

What else can I do besides manual chlorine addition (not technically legal) or dumping water?

 

[freqz]

*You can go with automated liquid chlorine. I know we have an outfit around here that will deliver bulk 12.5% to commercial locations starting at 100 gallons...Maybe a couple of grand for the pump, automation, install, and tank?

*Or you could switch to a cal-hypo feeder for the rest of the year of the elevated CH wouldn't cause a problem.

*Chlorine gas? No idea on the cost here.

 

[echo]

Lithium Hypo.... only downside is its pricey

 

[tim5055]

You don't have your location in your profile, so I can't comment on the legality of manual addition, but what about automated additions? On the larger pools you are dealing with you would need larger tanks, but it would seem some of the Stenner pumps would be up to the task. You would have the up front cost of installing the pumps/tanks but that may be offset over time with the reduced cost of liquid over tabs.

 

[chem geek]

The following rules are independent of concentration of product or of pool size so there's no point in trying to shop around for different Trichlor pucks as they will ALL do the same thing in terms of the amount of CYA for the amount of FC.

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (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 Calcium Hardness (CH) by at least 7 ppm.

 

[Hilton]

Thanks for the info, chem geek. I was aware of it, but I was unsure if someone made a special puck. There are some non-standard pucks out there, so you never know until you ask.

Unfortunately, these locations don't have the money to spend on extra equipment, nor could I mount it legally. As it stands these two particular pools are already operating against WCB and common sense requirements (all equipment is in one room, including the heater and chlorine feeder - as were the chemicals until I took over and made them buy outside storage containers), but they are grandfathered in. There is no way I could install a liquid chlorine feeder in those rooms. I have considered it, beleive me.

There are some pretty strong warnings about using cal-hypo (or any other) pucks in a feeder that had another product in it...and the feeders have strong warnings to use ONLY trichlor in them. So for cal-hypo pucks I guess I'd have to install a new feeder...which again I can't do "legally", nor would I likely be approved to spend the money.

It sounds like my only options are to use liquid cal-hypo like I did last year, or dump water. As I suspected. Ah well, it was worth a shot!

 

[y_not]

I should point out that your minimum FC level at 60ppm cya, is 5ppm, not the 2-4ppm FC that you said you are maintaining in your original post. You're asking for an algae bloom, especially if you have no reserve FC for bather load, UV consumption, etc..

Sounds like a classic case of a business, or even private entity, wanting to cut corners because they "don't want to spend any money to upgrade", to the point that they end up costing themselves more money in the end, due to excess labor and un-calculated "trickle costs" cumulative over time.

On a personal level, from my own experiences in a career as a service professional, I feel your pain. As a business man, I say drop them and run, if you can. It's not worth it, nor is your sanity. :banghead:

Sent from my PC36100 using Tapatalk 2

 

[chem geek]

Thanks for the info, chem geek. I was aware of it, but I was unsure if someone made a special puck. There are some non-standard pucks out there, so you never know until you ask.

The CYA in Trichlor and Dichlor is not added as a separate ingredient. It's part of the chemical molecule itself -- basically a CYA molecule that has some hydrogens replaced with chlorine. So the ratio relationship is constant for that molecule so it is impossible to have Trichlor with less CYA per FC or Dichlor with less CYA per FC than I had indicated.