Newbie hot tub owner requires some help

[Jpeterson]

Hi everyone, 

First, let me introduce myself. My name is Jamie and I am 23 years old. I live in the UK in a place called Durham. We are in the process of doing some extension work on our property, and as part of the work, we decided we would treat ourselves to a hot tub, something we've wanted for a while! So, our hot tub was delivered a week ago and the guys who installed the tub gave me a quick run down on the chemicals. Once the tub was filled (1100l) and up to temperature 38.5c (101.3f), I proceeded to do what the installers has told me. 

I tested the water first of all using the strips that has come with the tub. The strips measured free chlorine, pH and Alkalinity, all of which were lower than needed. They had told me to firstly get the alkalinity correct (80-120ppm on the strips) which I done by adding pH plus (Sodium Carbonate). Once the alkalinity was correct, I was told to then correct the pH (between 7.2 & 7.8). Since pH plus has increased the pH, it was now too high. I then added pH minus (Sodium Hydrogen Sulphate), which knocked the Alkalinity down to around 80ppm and got the pH at around 7.6-7.8. So far so good. I added the chlorine granules last using the recommended amount for our tub size. My final test showed that the tub was ready to use (Alkalinity: 80ppm | pH: 7.7 | Free Chlorine: 5ppm). 

We started to use the tub and everything was good for a few days. I tested the tub daily and notice that the pH and Alkalinity was dropping quite a lot, so I kept topping it up with pH Plus. I was adding the daily chlorine does as suggest. After a few uses of the tub we notices that we were getting some foam, not a huge amount but enough to notice. I couldn't work out why since we showered before using the hot tub, we hadn't washed out swim wear in detergent and all the water stats seemed fine. 

That is when I started to look online and confuse myself even more. Lots of people were saying lots of different things. Some contradicting others etc. I realised that I hadn't tested the hardness of the water. It turns out our water is really soft water, therefore we should have added calcium increaser. I also realised that we should have a non chlorine shock chemical so that we can shock the tub every week or so. I have read about all sorts of things that can cause damage to the tub and it's pumps and heater if the water chemistry isn't correct. 

So, I decided I would seek out a forum where I could get some help from experienced hot tub owners. Here I am. 

[MPurcell]

You will need to obtain a proper test kit. Strips are not reliable enough. In England it's a bit harder to find the correct kit. See this thread, and there are probably others on here.

If you plan to use chlorine as a sanitizer, you should follow the Dichlor/bleach method in a nutshell posted as a sticky in this forum.

I suggest you avoid pool stores and pool store advice as much as possible. You may need to purchase some supplies there, but don't let them sell you supplies. For this purpose, you need to educate yourself as thoroughly as possible. There is lots of good information on this forum, and also on Trouble Free Pool forum.

A few pieces of advice about chemicals. You can get much of what you need at the grocery store. For instance, pH up (sodium carbonate) is washing soda, and total alkalinity up (sodium bicarbonate) is baking soda. You can also use borax to increase pH without increasing TA. For chlorine, you can use household bleach, just don't use the scented or splashless variety as they have additives which you don't want. Items you will need to purchase at the pool store or online include muriatic acid, calcium carbonate to increase hardness, and dichlor to increase the cyanuric acid up to 30 or 40 ppm in the first week or two after a fresh fill. You should not use non-chlorine oxidizer as it's chemical formula can be hard on the equipment as it builds up. Use bleach or liquid chlorine instead. You should not use pH down or dry acid (sodium hydrogen sulfate) as the sulfates are hard on the equipment. Use muriatic acid instead.

You don't need to shock the tub weekly. With correct maintenance you will keep the sanitizer at the correct level at all times. You will add chlorine after soaking as an oxidizer based on the number of bather hours and temperature.

[Jpeterson]

Thanks for the reply MPurcell! 

I seem to have found a pool and spa chemical producer just around the corner from us. They seem to sell everything and at a really cheap price! The only thing I am struggling to find is Muriatic Acid (aka Hydrochloric Acid). I can only find pH down which is sodium bisulphate. 

I am assuming Cyanuric Acid is the same as stabilised chlorine granules (Sodium dichloroisocyanurate dihydrate)? 

I have also found the Taylor K-2006 kit on eBay for around £88. A little more expensive than for you guys, but worth it I think? Here is the kit on Ebay

Here is a list of the chemicals I've sourced from the local company:

Alkalinity Increaser (Sodium bicarbonate)

pH Up (Sodium carbonate)

pH Down (Sodium bisulphate)

Hardness Increaser (Calcium Chloride)

Stabilised Chlorine Granules (Sodium dichloroisocyanurate dihydrate)

Liquid Chlorine (Sodium Hypochlorite)

[MPurcell]

Actually the stabilized chlorine granules you mentioned, also commonly referred to as "dichlor", contain both chlorine and cyanuric acid (CYA). The formula for cyanuric acid is 1,3,5-triazine-2,4,6-triol, and can also be obtained separately under the name stabilizer. In the dichlor/bleach method you would add dichlor only until you reach a certain CYA level, then switch over to bleach (liquid chlorine - sodium hypochlorite).

The Taylor K-2006 is excellent and one of the most recommended test kits. It has everything you need. I know the test kits are a bit pricey, but if you follow the methods taught on the two forums you should save multiples of that amount of money in the long run.

Regards, Michael

[Jpeterson]

Ah, perfect then. 

So, the only thing I don't seem to be able to get is Muriatic Acid. The only thing I can find is sulphate based. Is there anything you can suggest? 

Also, Borates... I don't seem to be able to find anything to increase those. Can you suggest anything?

I shall get the K-2006 kit ordered now as it will take a couple of week to arrive. 

[MPurcell]

Look for online suppliers of boric acid. A quick search indicates that you will find some available in England. Try to get the granulated rather than the powder, as it dissolves much easier. Boric acid is relatively pH neutral (I know, it is counter intuitive) so adding 50 ppm won't mess with your chemistry balance. In the US I buy from Duda Diesel and there are a couple of other online suppliers, but I don't know about international shipping. There is plenty of information on the forums about increasing borates.

As far as muriatic acid, a quick search indicates that pool stores in England do carry muriatic acid. In the US, you can also get it at many of the big box stores such as Walmart and Lowes in the pool supplies section. Muriatic acid is also used to clean brick and concrete, so suppliers for those trades may be a possibility as well. Be aware that it comes in various concentration levels.