no chlorine

[jemae]

Sorry i didn't mention it earlier, my pool is inground concrete and i use normal mosaic. That is why I'm a bit worried about water hardness.

I'm going to the local pool store tomorrow, they said i should change to tablet which is about 90% chlorine for a while. I don't know what it is yet.

That is the problem I faced here, to get calcium chloride also is difficult. I will let you know the soonest.

The ph also start climbing since I put about 2 kg of household salt. (Again following their advice to increase hardness). It is about 7.5 now. Now, can i add hyrochloric acid? Lowering the PH and at the same time increasing the stabilizer?

Thanks

[jemae]

By the way, the chlorine that I use is Calcium Hypochloride as I mention earlier. It content 700grams /kg, which they said is 65%.

I will check on the tablet, infact just call them and they are hunting for the correct LONG name..

[chem geek]

I'm sure the tablet is Trichlor since that's the only chlorine that is 90% (approximately -- pure Trichlor is 91.5%). The ingredient name is trichloro-s-triazinetrione or trichloroisocyanuric acid. It's very acidic and for every 10 ppm of Free Chlorine (FC) that it adds, it also adds 6 ppm to Cyanuric Acid (CYA). The main advantage to Trichlor is that it is slow dissolving so you can put it in a feeder and not have to add it every day or so. However, if you want to get your CYA level higher faster, then it's more efficient to use Dichlor as your source of chlorine (or to use pure CYA, but that's slow to dissolve) for a short time until you reach the desired CYA level. After that, you switch to an unstabilized source of chlorine.

As for raising Calcium Hardness (CH), if you can't get calcium chloride, then that seems nuts. What in the world do they do in your area to add enough calcium to plaster pools to ensure the water isn't aggressive and etching the plaster? I noticed that here is a manufacturer of calcium chloride in Malaysia. Again, I suggest you try some other pool stores as I'm sure they all can't be that incompetent.

There is no reason for you to add regular household salt as that will do nothing to protect your plaster. I don't understand why it raised the pH -- regular salt won't do that by itself. However, if you use Cal-Hypo or any other hypochlorite source of chlorine, your pool's pH may slowly rise over time due to the normal outgassing of carbon dioxide from the pool (pool's are essentially over-carbonated -- that's what Total Alkalinity is mostly composed of).

Muriatic Acid will lower the pH but it will NOT add any stabilizer. Do NOT add any Muriatic Acid now -- your pH of 7.5 is fine and in fact you don't want a low pH right now because your CH is way too low. Stabilizer is Cyanuric Acid, not Muriatic Acid. Does your pool store sell something called stabilizer that says Cyanuric Acid in the ingredients? If so, then you can get some of it, but it dissolves very slowly so you'd have to put it in a sock or panty hose and hang it over a return to dissolve it in a couple of days. That's why I suggested you get Dichlor for chlorine instead since it dissolves quickly and will add both chlorine and Cyanuric Acid at the same time.

If you start adding CYA via either pure Cyanuric Acid stabilizer or via Dichlor or even Trichlor, be sure you keep track of how much you add since you do not want to add too much. Don't go above 30 ppm CYA for now.

If you were, over time, to cumulatively use 120 ounces weight (3400 grams) of Dichlor, then that would add 30 ppm CYA in 15,000 gallons. It's cumulatively 33 ppm FC so if you used 12 ounces at a time for 3 ppm FC (perhaps every day, if that is your chlorine usage), then it would take 10 days to get up to 30 ppm CYA. If you were to get pure stabilizer CYA instead of Dichlor, then that's about 60 ounces weight (1700 grams).

Richard

[jemae]

Wow, now i get really confused...

You are right, the tablet with 90% chlorine in it is trichlor.

Let me try to summarized my understanding, Now I am using Cal Hypo which add 2.7 ppm FC and 1.9 ppm CH each time I dosed the pool. I started the pool on the 10th March, about 40 days ago. CH will rise to about 80 ppm plus the original 80 when i started the pool, it should be around 160 ppm. As for the FC, it is consumed to fight the algae. You said before, using either Dichlor or Cal Hypo will also increase CYA. Am i right to say that my CYA is too high and the Cal hypo is not really effective? The problem now is, I can't measure CYA.

As for the Tri chlor, it will add 10ppm FC and 6ppm CYA. Should I use it for about one week to bring the CYA to desired 30ppm? (problem again since I can't test CYA). But, when I started the pool, I didn't add any kind of acid, so I assumed the pool does not have any CYA. Does the Cal Hypo I'm using increase CYA?

With my limited source here, I can try looking for unstabilised chlorine, if not, can I continue using the Cal hypo I have, keep an eye on the CH and dilute as necessary?

The thing is, the water is crystal clear. I use 1 HP Aquatight pump with Hurlcon ZX75 and the pump runs 8 hours a day. From 5 pm to 11 pm and 8 am to 10 am.

This weekend I'm going to Perth, the first order is searching for test kit. Any other thing I should get? Already ordered Barracuda G4 and a spare cartridge.

I hope I get it right before things get out of hand.

Cheers

[jemae]

got all the stuff i need from perth. In the process of chunking all the stuff in my pool.

Thanks for everything.

[chem geek]

I'm sorry I confused you. Cal-Hypo does NOT add CYA to the water. It only adds to CH. It is Trichlor and Dichlor that add CYA to the water. So yes, you can continue to use Cal-Hypo and monitor the CH to make sure it doesn't get too high.

I'm surprised there is no test kit in Australia that tests for CYA. I found this site in Australia that sells Taylor kits and at least has the K2005C, but ask them if they have the K-2006 (A or C) as the FAS-DPD chlorine test in the K-2006 is better.

As for whether chlorine is effective at your higher CYA, the answer is yes, it is always having some effect. It's just that at higher CYA levels it takes a higher FC level to have the same effect and at some point algae can grow faster than the chlorine kills it. Since your water is clear and you are not seeing unusual chlorine demand (drop in FC overnight) then you are in good shape so don't worry about it.

You can manage water where you are using stabilized chlorine such as Trichlor by either regularly diluting it or by using a supplemental algaecide such as PolyQuat 60 or a phosphate remover in maintenance mode, both on a weekly basis. It's more expensive, but will ensure you don't get algae. At some point, though, you do want to know the CYA level since the TA level needs to climb to maintain proper saturation of the water to protect plaster/concrete surfaces. You can determine the saturation index at The Pool Calculator link I gave earlier. If the index is very negative, then the water has the potential to etch plaster/concrete. It's a rough index of potential, however, so don't sweat it if it's just -0.3 or something like that. If it's below -0.6 or so, then look at increasing it. You've already been adding Calcium Hardness (CH) via the Cal-Hypo so are on the right track. I usually target my pool at around -0.2 to -0.1 so that in the gas heater it doesn't get over-saturated (higher temperatures can precipitate scale).

Richard

[Fabianj]

I opened my pool on May 6th. The water was dirty but cleaned up after 3 days by running the filter 24/7 and adding liquid shock to the water along with an algacide that the pool store said I should use.

My problem is that I can't get a free chlorine reading on my test strips.

I have taken a water sample to the pool store on two different occasions (May 9th and May 21st). The first time the water showed readings of:

May 9th readings
Free Chlorine: 1.1 ppm
Total Chlorine: 4.2 ppm
Combined Chlorine: 3.1 ppm
pH level: 7.3
Hardness: 120 ppm
Alkalinity: 134 ppm
Cynuric Acid: 55 ppm

May 21st readings
Free Chlorine: 0.2 ppm
Total Chlorine: 3.1 ppm
Combined Chlorine: 2.9 ppm
pH level: 7.8
Hardness: 90 ppm
Alkalinity: 102 ppm
Cynuric Acid: 60 ppm

Why would the level be zero on the test strips when I am using chlorine through the chlorinator at a rate of 5 3" tablets per week?[/b]

[jemae]

Thank you for all your help. Been queit for a while monitoring my pool readings after i got back fr perth with all the stuff. All the readings is stable.

Total chlorine 4
free chlorine 3
total alkaly 80
ph 7.2
cya 30
total hardness 250

Hope it will stay that way. Also got zodiac g4. Quite good, besides it refuse to climb the stairs.

[chem geek]

I have taken a water sample to the pool store on two different occasions
:
:
Why would the level be zero on the test strips when I am using chlorine through the chlorinator at a rate of 5 3" tablets per week?[/b]

I wouldn't trust the pool store numbers. For test strips and DPD drop tests (the latter measuring intensity of pink/red), high chlorine levels can bleach out the test having you think there is no chlorine when there is a lot. The OTO test (measuring intensity of yellow) won't bleach out, but the best chlorine test is FAS-DPD where you count the drops and can measure up to 50 ppm. Get yourself a Taylor K-2006 test kit which you can get at a good online price here or the TF100 from tftestkits(dot)com here with the latter kit having 36% more volume of reagents so comparably priced "per test".

Your pool store tests say that the Total Chlorine is higher than the Free Chlorine which means you've got Combined Chlorine, but that is unusual in an outdoor pool exposed to sunlight unless you've got ammonia in the water or are fighting an algae bloom.