Jimmie

Just to follow up on this. I added boric acid which tamed the pH. Hot tub water has been clear and a doddle to maintain since refilled at the end of December (5 months). Thanks all.

@Ahhsomeguyare you a dichlor only guy or dichlor and bleach guy?

Also this time I intend to stabilise the TA and pH using the slower method over a few days rather than the method in Nitro’s guide.

I’m currently running another purge. There is still some yuck coming out. Nowhere near as much as the first time though and far far more foam. Yes I only put 3 teaspoons in. I thought it was going to overflow with foam!

It was discoloured and sticky.

Very recent. 26th August. Flushed out with Ahh-soome. Cleaned the shell. Ran pumps briefly to eject water then vacced out the rest. Refilled, shocked. Usual drill. As I said, my CD is 29%.

The thing is the pH was 7.9 or greater the morning after. That's a good 12 hours later. I use a PoolLab 1.0 digital photometer. PoolLab® 1.0 - Water Treatment Products The liquid pool chlorine is stated to be 12-15%. I make it to be 10% judging by how much I need to raise by 1ppm and my tub size. My last session I raised the FC to 10ppm for a weekly shock. That was 105ml or 7 15ml doses (15ml per 1ppm raise). The time before that I only needed to raise it by 4ppm to raise it enough to have more than 2ppm in the morning. On both these occasions the water was cloudy in the morning and pH still high. Adding just pH minus resolved the cloudy water without constant filtering.

I'm experiencing repeatable cloudy water with the dichlor/bleach method. I have followed Nitro's guide carefully. I understand all the steps and the process. I got my TA down to 54ppm with pH under 7.6. My CH is 264ppm (hard water) and CYA is 37ppm. I have perfectly clear water until the morning after a two-person one hour session in the tub. After the session I top up the FC with liquid pool chlorine and the next morning it's cloudy with pH risen to 7.9 or beyond. I expect that the high pH has caused the dissolved calcium to come out of solution making the water cloudy. I put in enough pH minus (dry acid) to lower the pH and it clears in a few hours without filtration. I've never let my chlorine drop to below 2ppm and my CD is about 29% so I know it isn't due to poor sanitisation. I haven't added borates (boric acid, borax etc) as it is banned in Europe/UK and only available to professional trades. I'm pretty sure the liquid chlorine plus the aeration is pushing the pH high enough for the calcium to come out of solution. Here is a link to the liquid chlorine: 5 LITRE BOTTLE OF LIQUID CHLORINE (lincsproducts.co.uk) This has happened twice and both time I have recovered with pH minus alone. I've owned my hot tub for 3 years running dichlor and not had this particular problem before. I've only recently this week tried the switch to dichlor/bleach method. Any clues what might be going wrong? The liquid chlorine specification looks to be the correct one to me for this method.

Hi. I’ve owned a hot tub for about 3 years and just come across this site and its wealth of information. Incredibly useful and great to understand what actually goes in in the hot tub chemically wise. However, I’ve not seen mentioned anything about a product by ClearWater called “Stain and Scale Controller”. The ingredient is Etidronic Acid according to the bottle label. No I am guessing as there doesn’t seem to be a mention of this product or something similar that the consensus is that in a balanced tub, it’s not necessary. My calcium hardness is 234ppm if that’s of any use. So what are the expert’s thoughts on this stuff? How would it affect the chemistry of the tub/balance? Is it of use or a waste of money? Dosage is 18ml a week in a 1200litre tub - initial fill dose of 30ml. Thanks, Jimmie