Shopping around for 10%-12% chlorine

Postby **Henry_R** » Thu 25 Aug, 2011 08:29

My HOA is using 10% chlorine liquid in our HOA community pool. We just got 5-4 gallon bottle cartons which is $14 per at a local pool store. All we can find is 10% at this store. This comes equal to $3.74 per gallon of 6% walmart brand bleach and it's (40%?) stronger, but I'm wondering if we should search out a lower cost source or if there is such a thing?

Ordering online is likely not practical (or possible?) due to chlorine being a haz-mat right? So I local is the way to go. We're in Houston so we have lots of chemical companies... :roll:

Our chlorine demand is not too bad, but these gallons will only last a month or so with CYA=50-80 (TFT100 kit indicates 50 by my eyes, pool store reads 80 consistantly so it's somewhere in between there.) and a decent bather load after school. We used 1.6-128oz jugs (1 gallon, 2 quarts and 2 cups according to pool calculator) yesterday as normal chlorination and will need more about twice a week. Maybe more today since we've just had the first hard rain in about two months here in Houston and it may add some unwanted organics.
I'm going to check in a little while.

So other than a pool store what should we be looking for to shop around for 10% chlorine?

Postby **chem geek** » Thu 25 Aug, 2011 12:51

Try Warehouse Pool Supply, Walmart, Target or Costco as well as some Lowes and Home Depot stores.

With a pool that has a fairly high bather load, you should seriously look into automation such as a saltwater chlorine generator or a peristaltic pump or The Liquidator.

Postby **Henry_R** » Mon 29 Aug, 2011 09:15

chem geek wrote:Try Warehouse Pool Supply, Walmart, Target or Costco as well as some Lowes and Home Depot stores.

With a pool that has a fairly high bather load, you should seriously look into automation such as a saltwater chlorine generator or a peristaltic pump or The Liquidator.

Our bather load is really not that high. 8 people, perhaps 10 at most at any one time. This is not a very large pool 34x18 is what I think I've put in the profile.

The issue with the auto dosing equipment or SWG is cost. For the SWG it's electric demand vs our service panel supply. It needs probably low voltage for the control electronics right? Probably not much current.
What about the grid that that does the electrolysis? How much power does it need? I can't find any specs anywhere. We have only one dual-20A breaker for the pump which also powers the LED pool light, I think.
These condos were built in about 1971 as apts and converted to condos. The master meter was replaced by individual meters in the early 80s. The breaker boxes are a good 50 feet from the pool area. We have aluminum wire and Federal Pacific Electric panels which were decertified by UL and went out of business due to dual-pole breakers which didn't trip or tripped improperly and heated up catching fire. Unless our aluminum wire is sized such that we have enough current for the SWG it would be impractical to install since we'd need to rewire and the cost would be prohibitive given the cost of copper now.

The peristaltic pump and The Liquidator would each require installation by someone who's a pro with insurance. I'm sure I would be capable, but given this is my HOA pool they would not allow me to do the work since I have no insurance. The HOA GL insurance would actually cover it, I think, but there's a large deductable. I think so we'd have to pay for it ourselves in the end. Given a tight budget we cannot afford installation either for now. Perhaps if we hire a pool service at some point though.

For now manual dosing is the way to go until fall when hopefully a pool company will be hired and the chlorine demand goes down with cool temps.

Anyway, we have been going to warehouse pools so I guess that's the best.

Costco and others are not carrying more than regular 6% bleach. Even if they did I'd be concerned of stores here selling old stock. They even store the stuff outside most times which I believe is a no-no.

When the pool was closed in 2009 we tried some 12.5% chlorine from Lowes and the stuff was 6 mo. past it's shelf life. Instead of chlorinating the pool (it needed a good shocking) the pool turned green overnight.
Emailed mfg with date code and questions told date code was from January 2009, this was Mid-June. Complained to Lowes got a refund. Demanded compensation since it took 10x more 6% chlorine to bring the green back under control, but didn't follow up and manager left store for another.
After that I don't trust Lowes or anywhere else to sell fresh stuff.

Postby **chem geek** » Wed 31 Aug, 2011 21:05

An saltwater chlorine generator (SWCG) for 20,000 gallons putting out even 4 ppm FC during 8 hours of the day would be 10.7 ounces (about 300 grams) of chlorine. This is around 38 grams/hour or about 1 mole of chlorine gas per hour. It's 2 electrons per chlorine molecule produced so (96,485 Amp-sec/mole)*(2 moles of electrons) = 193,000 Amp-seconds per 3600 seconds or 53 Amps. However, this is at around 5 Volts (or in a bipolar cell system it's around 25 Volts with 10 Amps) and even with inefficiencies you are looking at no more than a 500 Watt SWCG unit and probably more like 300 Watts. I can't imagine that your wiring can't handle that. Your pump is probably close to 2 kilowatts of power.

Postby **Henry_R** » Thu 01 Sep, 2011 02:07

chem geek wrote:An saltwater chlorine generator (SWCG) for 20,000 gallons putting out even 4 ppm FC during 8 hours of the day would be 10.7 ounces (about 300 grams) of chlorine. This is around 38 grams/hour or about 1 mole of chlorine gas per hour. It's 2 electrons per chlorine molecule produced so (96,485 Amp-sec/mole)*(2 moles of electrons) = 193,000 Amp-seconds per 3600 seconds or 53 Amps. However, this is at around 5 Volts (or in a bipolar cell system it's around 25 Volts with 10 Amps) and even with inefficiencies you are looking at no more than a 500 Watt SWCG unit and probably more like 300 Watts. I can't imagine that your wiring can't handle that. Your pump is probably close to 2 kilowatts of power.

I'm just wondering if the wiring isn't on the edge of it's capacity inspite of a dual-20A breaker since alu cannot handle as much load as copper for the same wire size and should only be loaded for 70% (I think that's what I read) of it's capacity.
Mainly I have no idea what else might be tied to the same breaker. It should only be the pump and the pool light, but our wiring is 40 years old and very fooky due to the separation of each unit to individual meters from a master meter years ago. We have some units sharing electricity which should be isolated for example and had to be fixed.

A LV system this might be all A-OK. I was thinking the SWG was a 120V or 220V device at many amps. But if it
is a 5V or 25V unit then there's a step-down transformer pulling only a few amps and likely some electronics which probably includes a switch-mode power supply or similar to increase the current vs drawing it directly from the source. Interesting. Now if we can get the funds together and find a decent pool service to keep watch over the SWCG and not want to charge us $500 per month all would be good.