Calcium deposits?

jesper

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Also for polypropylene this link says the below, so again even a 20% solution isn't rated as A, so again I'm thinking a 10% solution would be safer.

Hydrochloric Acid 100%C-Fair
Hydrochloric Acid 20%B2-Good
Hydrochloric Acid 37%C-Fair

Ratings: Chemical Effect
A = Excellent.
B = Good, Minor Effect, slight corrosion or discoloration
C = Fair, Moderate Effect, not recommended for continuous use. Softening, loss of strength, or swelling may occur.
D = Severe Effect, not recommended for ANY use.
N/A = Information not available.
 

jesper

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Based on the manufactures data chart and this, chemical resistance of 37% HCL on Norprene is considered GOOD. no dilution needed for the pump tube itself.

The data for the polypropylene isn't promising. Looks like that may be your weak link and make the dilution necessary.
Thanks for checking, yes I think diluting is the safest option - and the more I've looked into it, the less I'm worried about it. I went and bought long chemical resistant gloves, protective eye goggles and a face mask.

I'm more worried about the potential issues of fumes from the HCL in the enclosed space, all the pool equipment is in an underground pit/basement where the only ventilation is two 100mm / 4 inch vent pipes, one of which has a humidity controlled bathroom fan installed.

Earlier in the thread I posted a schematic of one way to allow the acid container to suck air in as acid is dispensed, without having an open vent that fumes can easily escape from. I'm looking to find suitable containers and nipples to connect hoses, but I'm worried if I'll be able to make the connections sufficiently air tight that I won't have problems with fumes accumulating in the enclosed space.

From what I've read, HCL fumes are heavier than air and would accumulate at the lowest point, in my case that is the pit for the submersible pump, it is in a stainless steel box with a hole at the bottom that will drain into the soil below the machine room. If any fumes stay there, I can periodically rinse them out and they will end up in the soil below the machine room, but I'm not sure if I can rely on that, or if I risk the entire room being filled with acid fumes, and all the equipment being corroded as a result. Any ideas ?

Attaching pictures of the machine room.

Hatch in deck with entrance to machine room. The hatch is normally closed with a stainless steel cover and decking.

IMG_5382.jpeg

Below the ladder is the pit with the submersible pump, not visible here, but there is a drain hole to the soil below.

IMG_5383.jpeg

One end of the machine room, behind the ladder to the left is one of the 100mm vent pipes, to the right of the ladder is the other with the bathroom fan installed. The pipe in the middle is capped on the outside.

IMG_5384.jpeg

The other end of the machine room.

On the floor we have from the left:
1) the hydraulic pump for the cover
2) behind it the pipes to/from the pool
3) the pool pump
4) the acid tank with sulphuric acid still
5) the sand filter

Mounted on the wall we have from the left.
1) the SWG
2) the peristaltic pump
3) SWG + peristaltic pump controller
4) electric distribution board
5) control panel for pump etc.

IMG_5386.jpeg
 

Dirk

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I didn't follow any of that, but here's my logic (and what I apply to my system). My dilution provides the right amount of pH control at the minimum of acid "strength." That gives me two things: the minimum amount of wear and tear on the equipment, and the least amount of possible damage should the equipment fail and empty the acid tank into the pool. Win-win. A stronger mix would mean I would have to fill the tank less, but I only do so a few times a year anyway, so that's a fair trade off for me...
 
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frogabog

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@jesper, I have one concern about your setup and it is a big one (for me, and hopefully for you).

That is a confined space. Your acid tank is in there. You are adding the acid to the tank in there, presumably alone. I would like to express my concern over confined spaces and caution you about ventilation when you're in there. I have three suggestions...

One, add a fan that points up to the opening and run it 24/7. When you open the space to go in, wait 30 minutes with the door open before you go in. Alternately, install a ventilation system (better option).

Two, lock out the door somehow so that no one can close off the space when you're in there. Move the door to another location where no one can find it, or lock it out mechanically so that it can never be closed. Alternately, fashion some kind of unlocking device from the inside, although that could easily be bypassed by the outside if someone really wanted to. I'm not saying that someone might actually murder you, but stranger things have happened. Also, you do not ever want your kids to accidentally get locked inside.

Three, when you go in there, always tell someone and give them a time frame for you to emerge, or better yet have someone stand at the opening while you're in there to make sure you are safe.

Confined spaces have killed people even without chemicals inside. Insufficient oxygen alone could do a person in.

Now, after all that serious stuff... cool setup!!
 
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Dirk

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I was worried about fumes, and all my stuff is outside! Corrosion is the issue. There was a member here who told the story of everything in his garage getting corroded. He finally traced it to a sealed container of acid! Apparently, even some capped acid jugs vent (for some reason).

So all my acid supply lives outside, away from anything metal, in Suncast all-plastic storage bins. Since my acid tank/pump is mounted near all my other pool equipment, that, too, was a concern. I'm monitoring it. The Pentair tank is o-ring sealed, but has a vent to allow for expansion/contraction and dispensing. That vent accommodates a tube, which I ran well away from the equipment pad (on the other side of a vinyl fence, in fact), and I'm hoping that, plus the normal air circulation, will be enough to solve for corrosion.

With your setup, unless the acid dispensing equipment, including the tank, are 100% air tight, I'd wager all your gear is at risk. I don't think that well is going to solve for that. It certainly didn't matter in that guy's garage, which was a much bigger space and had at least some air circulation. The damage was not contained to the lower level.

I can't quite make out what you're explaining with your venting idea diagram. The tank has to be air tight, then run even a small tube from it to the outside, mimicking Pentair's solution. Otherwise, you could move the entire tank outside and then plumb the acid line back inside? For me, and my over-cautious ways, I wouldn't have anything acid indoors: pump, lines, injector, etc all outside, in the open air, and even then well away from any metal objects or structures. Just my 2¢...
 
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Dirk

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@jesper, I have one concern...
Confined spaces have killed people even without chemicals inside. Insufficient oxygen alone could do a person in.

Now, after all that serious stuff... cool setup!!
Sorry to harp on this... And maybe we're not seeing everything there is to see from the pics, but I think installing chlorine and acid machines in a confined space is a hazard. Frogabog is giving you some interesting solutions and safety advice, but those solutions, and the equipment itself, are all prone to failure. While some pool equipment failures can be expensive and/or inconvenient, they are rarely dangerous. But acid and chlorine when mixed together, correct me if I'm wrong, create a deadly gas. Add to that danger the nature of a confined space... I'll suggest it a second time, get that acid tank and all the dispensing apparatus out of that little room... Now that I think about it, corrosion isn't the primary concern...
 
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frogabog

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I re-read the post with the images and it does say there's a ventilation system, but it's a bathroom fan and I would not consider that enough ventilation. A high CFM fan would be a much better option. Even if the tank(s) and pumps are removed, a higher CFM fan would be a great idea.

The vapors, as you say are heavier than the air, but still... yeah that's scaring me, and I would not want to be in there myself, let alone someone I cared about. At minimum, please make sure someone is aware/standing by of your access and egress. Although this in and of itself poses additional risk to your second person. When one person is compromised in a confined space, the second person goes down to assist and also is overcome. Then two people are dead. It's an accident waiting to happen, and I think sooner than later.

I think Dirk's advice to move those out of the equipment room is the best idea ever. Chlorine and about anything combined (even soap/detergent - never combine these two) creates hazardous (deadly) vapors and I'm positive that acid and chlorine also do. What if one of those pumps leaks? What if both of them leak? I don't like it. At all.
 
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jesper

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Thanks for the input guys, some replies inline.

@jesper, I have one concern about your setup and it is a big one (for me, and hopefully for you).

That is a confined space. Your acid tank is in there. You are adding the acid to the tank in there, presumably alone. I would like to express my concern over confined spaces and caution you about ventilation when you're in there. I have three suggestions...

One, add a fan that points up to the opening and run it 24/7. When you open the space to go in, wait 30 minutes with the door open before you go in. Alternately, install a ventilation system (better option).

Two, lock out the door somehow so that no one can close off the space when you're in there. Move the door to another location where no one can find it, or lock it out mechanically so that it can never be closed. Alternately, fashion some kind of unlocking device from the inside, although that could easily be bypassed by the outside if someone really wanted to. I'm not saying that someone might actually murder you, but stranger things have happened. Also, you do not ever want your kids to accidentally get locked inside.

Three, when you go in there, always tell someone and give them a time frame for you to emerge, or better yet have someone stand at the opening while you're in there to make sure you are safe.

Confined spaces have killed people even without chemicals inside. Insufficient oxygen alone could do a person in.

Now, after all that serious stuff... cool setup!!
There is a fan, a small 100mm one through the vent pipe with return though another 100mm vent pipe. The fan was added to prevent extreme humidity, and it is currently on humidity control - but I can easily change it to run 24/7, I can also look for a 100mm fan with a higher CFM.

The hatch is covered by a stainless steel cover that is simply resting on top, on top of that goes a deck cover that again is just resting on top. From below they can simply be pushed aside as long as someone doesn't place something super heavy on top. Not too worried about someone deliberately trying to lock me in there.

About adding another fan in the cover, it would mean it would be exposed to the elements, rain water and splashing from the pool - it is only just over 1 meter from the edge of the pool. Not sure that is practical.

I was worried about fumes, and all my stuff is outside! Corrosion is the issue. There was a member here who told the story of everything in his garage getting corroded. He finally traced it to a sealed container of acid! Apparently, even some capped acid jugs vent (for some reason).
Yes HCL fumes can corrode pretty much everything, when we built the house the builder washed the tiles in an upstairs bathroom with HCL on a Friday afternoon and then left. Monday when I arrived I found door handles, door hinges etc. all corroded all over the house, even downstairs.

So all my acid supply lives outside, away from anything metal, in Suncast all-plastic storage bins. Since my acid tank/pump is mounted near all my other pool equipment, that, too, was a concern. I'm monitoring it. The Pentair tank is o-ring sealed, but has a vent to allow for expansion/contraction and dispensing. That vent accommodates a tube, which I ran well away from the equipment pad (on the other side of a vinyl fence, in fact), and I'm hoping that, plus the normal air circulation, will be enough to solve for corrosion.

With your setup, unless the acid dispensing equipment, including the tank, are 100% air tight, I'd wager all your gear is at risk. I don't think that well is going to solve for that. It certainly didn't matter in that guy's garage, which was a much bigger space and had at least some air circulation. The damage was not contained to the lower level.

I can't quite make out what you're explaining with your venting idea diagram. The tank has to be air tight, then run even a small tube from it to the outside, mimicking Pentair's solution. Otherwise, you could move the entire tank outside and then plumb the acid line back inside? For me, and my over-cautious ways, I wouldn't have anything acid indoors: pump, lines, injector, etc all outside, in the open air, and even then well away from any metal objects or structures. Just my 2¢...
Yeah, that certainly is safer and better to place everything outside in free air. In my case I cannot do that - the pipes to the pool in the last picture goes down through the concrete floor and pass under the pool to the returns, fully encased in steel reinforced concrete. No way to access them anywhere other than in this equipment pit.

Moving the tank outside, and have a longer suction tube is a possibility and much better from this perspective than having it in the equipment room. But outside I have to worry about how to prevent access to the tank, it would be right next to our decking.

I re-read the post with the images and it does say there's a ventilation system, but it's a bathroom fan and I would not consider that enough ventilation. A high CFM fan would be a much better option. Even if the tank(s) and pumps are removed, a higher CFM fan would be a great idea.

The vapors, as you say are heavier than the air, but still... yeah that's scaring me, and I would not want to be in there myself, let alone someone I cared about. At minimum, please make sure someone is aware/standing by of your access and egress. Although this in and of itself poses additional risk to your second person. When one person is compromised in a confined space, the second person goes down to assist and also is overcome. Then two people are dead. It's an accident waiting to happen, and I think sooner than later.

I think Dirk's advice to move those out of the equipment room is the best idea ever. Chlorine and about anything combined (even soap/detergent - never combine these two) creates hazardous (deadly) vapors and I'm positive that acid and chlorine also do. What if one of those pumps leaks? What if both of them leak? I don't like it. At all.
I don't use liquid chlorine, it is an SWG, so even if I have a leak it is effectively pool water with a very low concentration of chlorine, and for it to get mixed with acid, I'd have to have a simultaneous leak of acid as well. That seems very unlikely.

But your point about someone coming down to help is a real one.

I think I'll give up on the idea of using the pH pump to dispense HCL. And stop using the pH pump in general, instead I can manually add HCL directly to the pool as needed.

If sulphuric acid is safe to keep in the equipment room, I could keep the pH pump as a backup dispensing sulphuric acid for times when we're away for longer periods of time. From a quick search, sulphuric acid doesn't have anywhere near the issue with fumes that HCL does.
 

setsailsoon

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Jesp,

I'm late to catch up with this thread. Just want to add my $.02 on confined work space. I spent a lot of my career in chemical plants and refineries doing large expansions. Confined work spaces are a recognized hazard and require special permit procedures to mitigate the risk of entry. Not that it can't be made safe, just that it requires a lot of training and specialized equipment in a controlled environment that just doesn't exist in a home vs a chemical plant. Is there any way to just move the acid storage and equipment above ground in open air?

Hope this helps.

Chris
 
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jesper

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I'm late to catch up with this thread. Just want to add my $.02 on confined work space. I spent a lot of my career in chemical plants and refineries doing large expansions. Confined work spaces are a recognized hazard and require special permit procedures to mitigate the risk of entry. Not that it can't be made safe, just that it requires a lot of training and specialized equipment in a controlled environment that just doesn't exist in a home vs a chemical plant. Is there any way to just move the acid storage and equipment above ground in open air?
Thanks a lot Chris, it confirms that I'm better off not using the pH pump for HCL. Having the rest of the equipment, pool pump, filter and SWG in the equipment room should be fine.

Do you know having the sulphuric acid in there would be considered a hazard ?
 

frogabog

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I think you've got a handle on this, and you won't be the first person to add acid at pool side when you need to. In fresh air, by your pool, enjoying being upwind and having a moment with the pool. It'll almost be like if you got to add chlorine every day. I actually enjoy my 3 minutes with the pool every night. Even if I put it off and don't want to, it's a nice moment watching the bleach hit the return flow with the light on.

I do want to add, that my first suggestions were extremely lax and probably not good enough.

For the moment, you do have acid in that space. You don't likely have the proper ventilation. And you don't have a safety plan yet. Hopefully you will sit down and plan with your family some things that are required for your entry into the confined space. Especially when the acid is involved. I'll let others tell you about the chemistry. I don't have my reference materials handy atm.

I'll start some suggestions:

  • Ventilate 24/7 (where is the entry point for fresh air? If none, make one)
  • Open the space no less than 30 minutes before entering (I feel this should be considered as a requirement to proceed, no exceptions).
  • Always have a second person on watch
  • Maintain constant verbal contact with that person
  • Set a time of no contact at no more than 10-15 seconds. Make verbal contact regularly. Just describe what you're doing while you're down there, you don't have to think and make conversation that way.
  • If there's no contact in 20-30 seconds, that is the time to call emergency. This should be the rule, without exception. It's both your job to keep talking.
  • Second person is NEVER to enter the space if you are compromised. They must call emergency and wait. The simple fact that you are compromised insures that they will also be compromised.
  • WAIT till emergency arrives, no matter what.

And tell the fam not to put anything heavy on the hatch :~}

Please have a safety talk with the kids, this is not a play space.

Oh, and move the acid storage tank out of there right away. When using the pump, try to only put enough acid in the tank for vacation length if you're going to add it pool side instead when you're there. Run it dry after your vacations. This will reduce your exposure when you enter the space for non-related reasons.
 
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jesper

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I think you've got a handle on this, and you won't be the first person to add acid at pool side when you need to. In fresh air, by your pool, enjoying being upwind and having a moment with the pool. It'll almost be like if you got to add chlorine every day. I actually enjoy my 3 minutes with the pool every night. Even if I put it off and don't want to, it's a nice moment watching the bleach hit the return flow with the light on.

I do want to add, that my first suggestions were extremely lax and probably not good enough.

For the moment, you do have acid in that space. You don't likely have the proper ventilation. And you don't have a safety plan yet. Hopefully you will sit down and plan with your family some things that are required for your entry into the confined space. Especially when the acid is involved. I'll let others tell you about the chemistry. I don't have my reference materials handy atm.

I'll start some suggestions:

  • Ventilate 24/7 (where is the entry point for fresh air? If none, make one)
  • Open the space no less than 30 minutes before entering (I feel this should be considered as a requirement to proceed, no exceptions).
  • Always have a second person on watch
  • Maintain constant verbal contact with that person
  • Set a time of no contact at no more than 10-15 seconds. Make verbal contact regularly. Just describe what you're doing while you're down there, you don't have to think and make conversation that way.
  • If there's no contact in 20-30 seconds, that is the time to call emergency. This should be the rule, without exception. It's both your job to keep talking.
  • Second person is NEVER to enter the space if you are compromised. They must call emergency and wait. The simple fact that you are compromised insures that they will also be compromised.
  • WAIT till emergency arrives, no matter what.

And tell the fam not to put anything heavy on the hatch :~}

Please have a safety talk with the kids, this is not a play space.

Oh, and move the acid storage tank out of there right away. When using the pump, try to only put enough acid in the tank for vacation length if you're going to add it pool side instead when you're there. Run it dry after your vacations. This will reduce your exposure when you enter the space for non-related reasons.
Thanks for the advice, and you're right I better get the acid out of there ASAP.

Once the acid is removed, there is no hazardous materials left in the there, and I can probably get away with slightly less rigorous precautions. But until the acid is out and I've drained all the existing pipes for acid, or if I ever put it back to use the pH pump in the future, precautions like you describe above with a 2nd person to keep an eye on me, and call emergency services if need be, is for sure a good idea.

Regarding ventilation, there is a 100mm pipe for entry of fresh air, separate from the pipe that has a fan for extracting air from the space. Next time I'm out there I'll flip the switch so the fan runs 24/7.

Our son is 10 years old, he knows that this is a no-go area - but I'll remind him, in general he is quite a careful and well behaved kid, so I'm not worried about him doing things once we have explained it is dangerous, and why.
 
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jesper

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Yes, sulphuric acid would have similar hazards.
However, sulphuric acid should not be used in the pool. The sulfates are bad for the SWG itself and not good for the plaster as well. You should use muriatic acid.
Thanks for the confirmation, I'll get the sulphuric acid out of there ASAP. I'll need to find a safe storage / disposal for it, I don't want it inside the house or in our basement, nor do I feel safe storing it out in the open.

This thread started with me finding out that the sulphuric acid supplied by the pool company was unsuitable for pool use. It then turned into me exploring how I could safely use HCL / muriatic acid instead. And finally we have concluded that the fact my equipment is in a confined space, means that I cannot safely store acid there, and thus cannot use the pH dosage pump. Instead I'll manually add HCL directly to the pool as needed.
 
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setsailsoon

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Thanks a lot Chris, it confirms that I'm better off not using the pH pump for HCL. Having the rest of the equipment, pool pump, filter and SWG in the equipment room should be fine.

Do you know having the sulphuric acid in there would be considered a hazard ?
Yes, it definitely would be considered hazardous. I worked the first part of my career as a process engineer in an alkylation plant that made gasoline blending components. The main reactors used sulfuric acid as the catalyst. It was considered extremely hazardous, required special gear, and confined work space permits for entry into any confined space that contained any H2SO4. Specially trained Safety personnel had to sniff with detectors to demonstrate safe conditions before anybody could enter. Entry permits required renewal each shift. There are a lot of additional details but I think you get the point. HCL and H2SO4 are dangerous but can be handled safely with proper protection. Introduction of either to a confined work space adds tremendously to the risk... not something to be done in residential environment.

I hope this helps and thanks for receiving this feedback in the constructive manner it was intended.

Chris
 
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jesper

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HCL and H2SO4 are dangerous but can be handled safely with proper protection. Introduction of either to a confined work space adds tremendously to the risk... not something to be done in residential environment.

I hope this helps and thanks for receiving this feedback in the constructive manner it was intended.

Chris
Thanks Chris.

Message received loud and clear, I really appreciate the help and guidance received here.

I spoke with the pool company, they will take back any unused sulphuric acid, so I don’t have to find alternative disposal methods.

Probably tomorrow I’ll remove the sulphuric acid tank and return it, but making sure I ventilate vey well before entering, and have someone on standby to call emergency services if required.
 

Dirk

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Great solution. But on to another word of caution. I stained my deck by mishandling muriatic acid. Here are some threads in which I explored a lot of what you're working through:

and
Around post #66 I explore acid-dispensing safety issues and gear.
Around post #97 I reveal my solution for adding acid manually, and while I'm happy with my IntellipH, I still use this solution from time to time when I need to dose manually.

If nothing else, heed the bucket trick. Don't carry anything-acid over your deck. Keep everything in a plastic bucket, and only transfer the acid jug to the water when the bucket is just slightly hanging over the edge of the pool. This simple MO will greatly reduce any errant acid drops from ever coming into direct contact with your deck.
 
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Dirk

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By the way, it's not your 10-year-old you have to worry about, it's his friends! A secret club room with ladders and hatches and knobs and dials... yikes. Waaaaay to tempting for young male minds. In one of my threads I explore ways to store my pool chems. I can trust my kids around them, but I lock them up for pool parties. There is an inverse principal involved that has led to who-knows-how-many pool-related accidents: the more parents there are at a pool, the less anyone is watching the kids!
 
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