robquick

Chem Geek, If the CC figure submitted is above the target of 0.5 it says that the tub needs shocking. However, if the CC level is 1 or as high as 10 the amount of chlorine is says to add is the same figure. If I change the CYA then the chlorine required changes massively. I assumed the higher the CC the more Chlorine would be needed to shock. On this app it appears that once the CC is high enough to trigger a shock its only the CYA that impacts the amount of Chlorine thats needed. Does that sound right ? I don't see a CC calculation on the program you mentioned ? Thanks.

Hi, I've downloaded a app for my iPhone that helps you calculate the quantity of chemicals needed to manage your tub/pool. The design and layout of the app is fantastic and it caters for FC, CC, ALK, PH, CAL, CYA and SI. Having played around with the app and reviewed the numbers it comes up with I have one question about management of Combined Chlorine. When calculating how much Chlorine is needed to 'shock' a tub that is experiencing high levels of CC what needs to be taken into account. Is it the current level of CC or CYA that dictates the required quantity of Chlorine needed to bring CC back in line ? Thanks.

Thanks. I've just ordered the bleach that you posted about earlier in this thread. Can bleach be damaging to any type of shell (not sure what mine is). Is there nothing I can do with Shocking or super chlorinating now?

CYA is 85 and I've been using Calcium-Hypo for the last two months, I use the tub about 2 or 3 time a week for 30 mins with 3 people. What's the best way to recover now? Do you think the CYA is causing the problem ? Thanks.

Hi, I recently purchased a professional water testing kit and was surprised having tested the water that my combined chlorine was 2.8ppm. I took the test kit back to the shop with a water sample and got the shop to test the water with my kit to ensure I was following the right process. They tested the water at the same level and then tested on their in house equipment which again tested at the same level. I'm religious with testing and adding chlorine on a daily basis, I also follow the 3.5 teaspoons per bather hour immediately after bathing (adjusted slightly down to compensate for Ozone). What am I doing wrong that has allowed my CC to get so high and what can I do now to resolve quickly? I regularly have chlorine levels over 20ppm immediately after bathing so I'm not really sure what else I can do. Finally what is an acceptable level for CC? My understanding is under 0.5ppm. Thanks.

Chem Geek, One other question, what strength bleach would you recommend ? Thanks.

Thanks for the two replies. Chem geek, I currently use one teaspoon of Calcium Hypochlorite daily (between soaks only), 24 hours later my FC will be around 1.5ppm ready for a potential soak. If I was to use the 14/15% bleach is it possible to calculate what the equivilant of 1 teaspoon of bleach is in ml ? Topspeed007, how long have you used the Tesco bleach for and what are the results like ? Thanks.

I guess the 12% pool bleach would be a better choice then. The size of the 25l container feels like its going to be a pain to measure such small volumes? Any suggestions?? Thanks.

Thanks. Should I be concerned with my CYA being do high ?

Hi, In the UK it appears impossible to purchase liquid bleach greater than 4% in strength unless you buy 12% bleach in 25l containers from a pool supplier. Would 4% supermarket bleach work ? Has anyone found a simple method of measuring out small volumes of bleach (20ml) from a 25l container without spilling on every occasion !!!! Cheers.

Hi, I've just purchased a Lovibond photometer and would appreciate some advice on the results. FC - 4.86 CC - 2.12 PH - 7.81 CYA - 89 TA - 54 Calcium - 160 I've shocked the tub to 25ppm 3 days ago, does the CC seem very high having just shocked ? What else can I do to bring the CC down? Is my CYA too high, I used Dichlor for about 2 weeks then switched to Calcium Hypochlorite about 4 weeks ago? My PH keeps rising to around 7.8, what's the best way to stabilise the PH? I would like to switch to bleach however, I worry it will damage the tub in some way, should I be concerned ? Cheers.

Thanks, is CC of 0.5ppm or more an indication of the need to shock?

Hi, My chlorine demand in a 24 hour window (in between uses) is about 50%, if I put 1 teaspoon of chlorine in daily my chlorine level will be at about 2.5ppm the same time the following day. If I'm going on holiday for 7 days what prevents me adding a much larger quantity of chlorine that would dissipate to a sensible safe level for my return? Is this a practical theory or am I way off track ?!?! Any help or guidance appreciated. Thanks.

Chem Geek, Many thanks for your helpful reply. Your numbers around chlorine demand match my demand 100% however, I don't understand why CD increases with ozone, can you explain so I fully understand the logic? I assumed ozone would reduce CD, as there would be less work for the chlorine to do, clearly I'm wrong. If my combined chlorine is less than 0.5ppm is there no need to 'shock'? I see frequent posts suggesting that you should 'shock' every week, which is the best theory to follow ? Thanks.

Hi, I'm a little confused with the term 'shock', rather than writting a two page essay I thought it would simpler to ask the following specific questions. Is 'shock' a process or a chemical ? If its a process, why is there a chemical called non-chlorine shock? Assuming its a process, how do I know when the tub needs shocking, is it when my combined chlorine exceeds 0.5ppm (or am I totally on the wrong track!) ? Can I shock the tub by adding a greater amount of Dichlor, if so what ppm should I be aiming for ? Any help or clarity appreciated.

Minicab, Thanks for the reply. It's for domestic use, some may say its a bit over the top for my needs however, I would prefer to pay a bit more for something that really does the job accurately. Would you suggest any other testing equipment in this price band ?? Thanks.

Hi, I'm thinking of buying the Lovibond MD100 6 in 1 water testing device, I would be interested in your opinions of this model. I've attached the link below. http://www.onlinepoolstore.co.uk/lovibond-md100-6-in-1-pool-control-107-p.asp Regards

My CYA is currently 40, is it ok to run the tub with the Alkalinity at just over 60? Thanks.

Thanks. Can I then control (reduce) the calcium levels with hardness reducer?

Hi, I'm trying to balance my water the Alkalnity is currently sat at 65 and Ph at 7.9. Can I simply use Ph reducer to bring the Ph back in line or will this reduce the Alkalinity to much ? Any help appreciated. Rob.

Hi, I currently use Dichlor only, having read various articles on this site I'm conscious about the impact this could have on CYA levels. I would like to avoid using liquid bleach (long story why) however, if I used Calcium Hypochlorite granules once the CYA exceeded 30ppm would this still achieve the same result in maintaining lower levels of CYA as liquid bleach would ? I think I read that using Calcium Hypochlorite will slowly increase water hardness levels too, is that correct? If so, do I just keep that in check with hardness reducer? Any guidance appreciated.

Thanks for the reply. My plan is to switch to bleach once I get my head around the basics which your advice is helping me to do ! If you use Dichlor only what life span would you get from the water roughly before the CYA level became a problem using a 1500l spa for 3 hours bathing per week? I'm guessing this is a 'how long is a piece of string' question however, just trying to work out how urgent it is for me to convert to the Dichlor/bleach process ? Thanks again.

Chem Geek, I've recently had a problem raising the FC levels beyond 1ppm. We used the tub loads over the Christmas period, in hind sight based on your numbers I didn't add enough Dichlor after heavy bathing. I've been using Dichlor only with occasional shock since early November with no problem. Can you please clarify that your 3.5 tea spoon calculation per hour per person applies when using Dichlor only too as opposed to the Dichlor and bleach process? Six of us used the tub for nearly three hours on New Year's Eve, am I right in thinking we should have used 6x3x3.5 (divided by two because I have ozone) = 31.5 teaspoons of Dichlor ??? Any guidance appreciated !

Chem Geek, I've recently had a similar problem raising the FC levels beyond 1ppm. We used the tub loads over the Christmas period, in hind sight based on your numbers I didn't add enough Dichlor after heavy bathing. I've been using Dichlor only with occasional shock since early November with no problem. Can you please clarify that your 3.5 tea spoon calculation per hour per person applies when using Dichlor only too as opposed to the Dichlor and bleach process? Six of us used the tub for nearly three hours on New Year's Eve, am I right in thinking we should have used 6x3x3.5 (divided by two because I have ozone) = 31.5 teaspoons of Dichlor ??? Any guidance appreciated !