frexpt Posted June 30, 2011 Share Posted June 30, 2011 Late opening our pool this year, but not in bad nick at all.........However, a bit confused because using the simple DPD & phenol tabs with water straight from the pool, I am getting quite low readings.....0.5 ch and 6.8 pH. The pool temp is 18C (always been a problem because shady site). However, if I leave the test kit in the kitchen for a couple of hours, the readings increase to between 1 - 2 ch and 7.2 pH.I put in about 3 litres of javel last night, expecting the ch to be higher this morning, but these are my results.......any thoughts please?(edit........pool about 45m3) Link to comment Share on other sites More sharing options...
Théière Posted June 30, 2011 Share Posted June 30, 2011 Yes temperature does affect results ad can taking the water sample from different points and depths. It is usually the test reagents that state the temp to carry out the tests at. Link to comment Share on other sites More sharing options...
chem geek Posted June 30, 2011 Share Posted June 30, 2011 If you let the chlorine test sit, then there can be bleed-through of Combined Chlorine (CC) reading as Free Chlorine (FC) and there can be other reactions as well. For the FC test you read it soon after mixing, but not more than one minute later. I don't think the temperature affected the chlorine reading, but elapsed time probably did.As for pH, it actually drops a little as temperature increases, but in your case I suspect that your Total Alkalinity (TA) may be on the high side and having the small sample sit exposed to the air had carbon dioxide outgassing increase the pH over time. Link to comment Share on other sites More sharing options...
Théière Posted June 30, 2011 Share Posted June 30, 2011 On the good news side the cooler pool will use a bit less chlorine Link to comment Share on other sites More sharing options...
frexpt Posted June 30, 2011 Author Share Posted June 30, 2011 [quote user="chem geek"]If you let the chlorine test sit, then there can be bleed-through of Combined Chlorine (CC) reading as Free Chlorine (FC) and there can be other reactions as well. For the FC test you read it soon after mixing, but not more than one minute later. I don't think the temperature affected the chlorine reading, but elapsed time probably did.As for pH, it actually drops a little as temperature increases, but in your case I suspect that your Total Alkalinity (TA) may be on the high side and having the small sample sit exposed to the air had carbon dioxide outgassing increase the pH over time.[/quote]That was exactly what I was wondering, in my own very simplistic way.[Www] I'll rely on the readings at the time they are taken from hereon.......Many thanks! Link to comment Share on other sites More sharing options...
frexpt Posted June 30, 2011 Author Share Posted June 30, 2011 [quote user="Théière"]On the good news side the cooler pool will use a bit less chlorine[/quote]As the ad says........."every little helps!"[:D] Link to comment Share on other sites More sharing options...
Théière Posted June 30, 2011 Share Posted June 30, 2011 Don't get too carried away you should have had closer to 6ppm after adding that much chlorine and if and I agree with chem geek you are showing combined chlorines at 2-3ppm then you need to shock the pool.i thought you meant the water was allowed to warm up in the kitchen before you tested it. Re reading your post I agree that test has been too long. Have you any DPD 3 test tablets? Link to comment Share on other sites More sharing options...
frexpt Posted July 1, 2011 Author Share Posted July 1, 2011 [quote user="Théière"]Don't get too carried away you should have had closer to 6ppm after adding that much chlorine and if and I agree with chem geek you are showing combined chlorines at 2-3ppm then you need to shock the pool. i thought you meant the water was allowed to warm up in the kitchen before you tested it. Re reading your post I agree that test has been too long. Have you any DPD 3 test tablets?[/quote] Sorry for the confusion...no, I just left the sample, as taken, indoors for a couple of hours. I haven't any DPD 3, but I'll try to get some tomorrow and also pH Plus.Just done another DPD1 and phenol red test........1 - 1.5ppm chlor and 6.8 pH. As it is quite warm, I thought the pool pH might have started to rise by now. In the past, keeping it down has been more of a problem. I'm wondering whether the low pH is affecting the efficiency of the javel, which was from a brand new bidon??The pool is clear, blue and sparkling, but I certainly don't want a repeat of last years nightmare with algae. I've got about 2 litres of javel, so could put that in this evening.......or do you think it better to try to wait until I can get the DPD 3 tabs and/or bring the pH up a bit?[8-)] Link to comment Share on other sites More sharing options...
Théière Posted July 2, 2011 Share Posted July 2, 2011 The lower Ph makes the most poweeful part of chlorine more active. It unfortunately can cause eye irritation. What level is you alkalinity?You can raise your Ph by bubbling air through the water or pointing your returns skyward so the water breaks the surface causing bubbles. That way you won't raise the Alk either Link to comment Share on other sites More sharing options...
frexpt Posted July 3, 2011 Author Share Posted July 3, 2011 I put some PH plus in last night and the Phenol red reading is now 7.6. DPD1 chlor test appears to be under 0.5 though. In addition, I couldn't get DPD3 tabs locally, so I settled for an Aquacheck dip set. Not ideal, I know, but these are the readings from that.....pH 7.2 - 7.8Free chlor 0 - 0.5total alk 40 - 80 ppmstabilizer 30 - 50 ppmNot sure what best to do next......more javel? Link to comment Share on other sites More sharing options...
Théière Posted July 3, 2011 Share Posted July 3, 2011 Now you need to dig a hole near the pool, not too big, I would think 100mm dia and 300 mm deep should do it.Next throw the aquachek strips in the hole and fill it back in.The range you reported is too wide to be able to advise but you have the Ph a bit high now.If the alk is roughly 40-80 then your Ph should be pretty stable and not drift up as time goes on so you should be able to lower the Ph to 7.4 before adding more chlorineThe CYA could be anywhere as strips cannot measure that acurately. Link to comment Share on other sites More sharing options...
steve Posted July 4, 2011 Share Posted July 4, 2011 MMM, new dip test strips purchased by customer with a 2013 use by date gave 8.4 ph, 1000ppm total hardness, and 1-3 chlorine....... actuals are 7.3 ph, 232 TH, and 2.6 free chlorine! Nice and accurate these dip testers!Steve Link to comment Share on other sites More sharing options...
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