Automated (liquid) chlorine doser for 330 gallon spa + foaming issue

[bassie123456]

I hope I post this question in the right forum, if it belongs somewhere else, please let me know!

Someone gave me a tip to post my question here, and so I will. Hopefully someone has experience on this matter or any advice. First of all, a short introduction of my situation. I live in The Netherlands and I have a 330 gallon spa. I use the spa 2 - 3 times a week at +/- 98.6 degrees. I have the spa for a little over 2 years now, and I have always had issues with maintenance and keeping the water clear. I shower before entering the spa, I clean the filter regularely, I re-fill the spa every 3 months, etcetera. Still, I never found the magic water maintenance method to keep it sparkling clear at all times.

Luckily for me, I started doing some research recently and discovered these great forums. There is lots of information and I have read so much to learn more about water chemistry, balance and sanitation. I have learned very much (thanks to some people that helped me explain things very clearly) and I now realise that I really had no clue of what was going on in my spa. The guys that sold me the spa gave me very little information, and the information was mostly build on how they could sell me as much products as possible.

Anyway, to summerize a long story: I recently switched to the dichlor-than-bleach method. Since then everything is going great. It was a bit though to start with this because it is pretty hard over here to get some products such as bleach with a specified concentration chlorine or borates, however I found all the stuff I needed and I drained the spa to start over with this apporach. For now, my water is clearer then it's every been.

Basically I have two questions and I hope someone has experience with this and can help me out.

1) automated chlorine doser
I travel quite regularely and although I like the bleach approach a lot, it requires me to check the FC levels at least every 2 days. I have an ozonator and my chlorine demand is pretty high. So I have been thinking about automating the chlorine supply to my spa. I use 12,5% bleach / liquid chlorine. I'd rather use houshold bleach with lower chlorine concentrations, but the only bleach they sell over here contains 'Less then 5% chlorine', probably between 1 - 4%. So that's not very specific and pretty low concentrated. So, I have been thinking, what if I could automatically add bleach to my spa every 12 hours for example. I have found a dosing pump on which I can set the interval and amount which should work. The pump is made for aquariums, but according to the store owner it will work just fine with chlorine on a spa. I was thinking about the following approach:

- Keep a bottle of 12,5% bleach next to my tub (should I store this in some kind of special container?)
- Drill a small hole in the cap of the bottle
- Put the silicone hose through the hol so that it gets close to the bottom of the bottle
- Maybe glue the hose to the cap so it won't move and is air tight (don't want chlorine fumes to escape)
- The hose from this bottle goes into the pump and out of the pump I have a hose which goes to the spa
- I would only set the autodosing once or twice a day, during filter times so that the water is moving when the chlorine is being pumped into the pool

Has anyone tried this kind of setup and what is your opinion on this? Does this work to auto dose the chlorine supply for a couple days or maybe even a week or so?

2) foaming issue
The second question I have is about a foaming issue I keep having. We shower before entering the tub and our bathing clothes are cleaned really well under tap water. Still, when the jets are on there is quite some foaming. Someone already helped me a lot on this and adviced to shock the pool or maybe try slamming the pool, because it could be stuff that needs to be killed. However, the spa has had quite some shocks untill now and the issue remains to be the same. It is not extreme foam like over my head, but it is a little bit annoying. Once the jets are off the foam is gone pretty quickly, but it leaves a white-ish residue on the surface. If the filter is on this is gone in like 1 - 2 minutes as well and the water is back to perfectly clear.

What could this possibly be and what could I try or test to learn more about whats causing this? I'd rather not use something like 'foam away' because that's not really a solution to the cause of this problem imo.

To conclude, here are my current values for the spa:
PH: 7.75 (digital meter), testing with Taylor kit seems a little bit lower but thats color interpretation
TA: 70-75
CH: 160
CYA: 35
Borates: 50

Thanks a lot in advance and sorry for the long post..

 

[JVTrain]

1 - another good option rather than attempting to set up a liquid chlorine dosing system is to purchase a salt water chlorine generator designed for spas and hot tubs. I'm not sure what will be available to you in The Netherlands but there are several options of SWG units that simply drop into your spa water and once you add enough salt to the water, they produce chlorine for you. Here's a couple of examples:
Saltron Mini DIY Chlorine Generators for Spas
ChlorMaker Spa Chlorine Generators

2 - You're not using a bleach product that is called "easy pour" or "splashless" or has other detergents in it? That would cause foaming. Very low levels of CH can cause more foaming but yours doesn't look that low. You could try raising the CH a bit to 200-250 but I doubt that's your issue. Check the ingredients on your chlorine source first.

 

[Demegrad9]

Definitely agree with JVTrain's initial assessment. Check your bleach product.

I use an auto-dosing setup but it's specifically made for injecting chlorine into pools. Can you provide a link to see this pump you're being suggested?

 

[ant 83]

Yeah, I think you need a special kind of hose, or the chlorine will oxidize it in short order.

Stenner makes pumps and hose that are specifically designed for this application.

I don't know what kind of winter temps you get, but although the freezing point of bleach is lower than water, it will freeze, especially in the tube. Perhaps you could rig up some kind of insulated box to keep your equipment in next to the tub. I suppose this isn't a problem if you're inside a heated space with the tub.


With the foam, get a pool net, and scoop the foam out. It goes away for me after about 10 minutes of scooping for me. I do this about every two weeks.

 

[bassie123456]

Thanks all for your replies and help!

I use 12,5% bleach (bought from a pool shop). It says '12,5% natriumhypochloriet'. It is thin (so not thickened or something like that) and defintely has no detergents in it. The color is lightly yellow, while a bottle of bleach with less then 5% natriumhypochlorite (which I recently bought) looks more clear / transparent. But that's probably due to the higher concentration chlorine? So I was thinking if the foaming could be caused by this, but then I remembered that in the first 1 - 2 weeks after my refill, I already had this same issue. And back then I only used dichlor to get my CYA level up. So it can't possibly be the bleach right? It even foamed a little bit before we ever got in the tub if I remember correctly.

Thanks for the tip on SWG system. I will look into it and do some more research. However, I already contacted my spa dealer and they say that they are currently testing and working on such system. They do not recommend to install it on my spa yet, but they do expect that they can install it for me in the future. I don't know if I lose warranty or anything if I install such system myself. Those mini SWG systems do seem pretty easy too use and not too expensive, so I will defintely look into that and discuss it with my dealer / manufacturer. I am not to confident in myself installing this on my spa but it actually does not look to difficult to install. This is the automatic dosing pump I was refering too: https://zeeaquarium-winkel.nl/1596-AquaHolland Doseerpomp kanaals met voeding (the website is only available in Dutch..)

If I start using a liquid chlorine doser I think it is a great idea to store everything in an insulated box so it's protected better from (extreme) weather conditions. Our spa is outdoors (but covered under a wooden construction). It could get quite cold in the winter and it does get quite warm in the summer. So the insulated box is a very good idea I think.

As for the foaming: I will try and increase the CH a bit. I will also try to scoop it out for a while with a pool net and see if it goes away. I have already scooped it out a couple times (not for 10 minutes however) and that did not really help. Also, because it is very unlikely that the foaming is caused by soaps, I think it's strange that it keeps coming back.

Thanks again everyone!

 

[bassie123456]

Hey guys. A little update on the foaming issue. The last couple days I have:
- Increased my CH to somewhere near 175ppm
- Been scooping foam out for a while 2 times

The foaming is less now, I think because of the scooping. Because during scooping I definitely see less foam formation. I don't really want to raise my CH much more because it will affect my balance to much.

I will try scooping a couple more times and see how it goes. It is absolutely not gone yet. The foaming itself is not really a pain because it goes away very quickly and because it isn't too extreme. What I still think is weird however, is the residue that the foam leaves on the surface. It takes around 2 minutes of filtering before it's gone completely.

I can see that the water below the residue is very clear and once the residue has been through the filter, the water is perfectly clear on the surface too. But I can't wrap my head around why the foam is leaving this stuff. I have been in tubs before with foaming, but it did not leave that kind of residue on the surface as far as I remember. Here's a pic of what it looks like. Does this ring any bells or does anyone recognize this?

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