Cheap muriatic acid drip feeder... would this work?

[aztodd]

I'm considering fully automating my pool to include pH management - due to high TA fill water where I live, my pH will always creep up to ~8.2 within a week (from 7.6) unless I add small amounts of acid each day or two. I realize there off-the-shelf systems for this, as well as CO2 injection systems, but these all cost a fair amount. I'm wondering if something like this would work https://www.amazon.com/dp/B09GYDBC7Y - an auto drip feeder meant for watering plants. The key question of course is, would the acid ruin this machine... depending on how it is designed, if the acid was always remaining within the tube, it seems at least plausible that this could function as I am hoping it would.

Curious to see what people far more knowledgable than me think about this out-of-the-box idea.

 

[ajw22]

@Dirk will tell you in many words why that is a bad idea.

Use a Stenner Pump or IntellipH that is built to handle acid.

 

[mas985]

You would need chemical resistant tubing. Normally, the stuff they use for water systems will deteriorate. If you dilute the acid enough, it might work.

There are cheaper versions of peristaltic pumps. I built one myself similar to this one:

Amazon.com: Pump Supplies - G728-1 Miniature Peristaltic Self-Priming Pump Small Circulating Pump 100-240V(22～85ml/min(G728-1-2)) : Industrial & Scientific

Buy Pump Supplies - G728-1 Miniature Peristaltic Self-Priming Pump Small Circulating Pump 100-240V(22～85ml/min(G728-1-2)) on Amazon.com ✓ FREE SHIPPING on qualified orders

www.amazon.com

Out of these parts:

https://www.amazon.com/dp/B07GP72BWV

https://www.amazon.com/dp/B08SCK9THN

 

[Dirk]

It won't work.

 

[aztodd]

You would need chemical resistant tubing. Normally, the stuff they use for water systems will deteriorate. If you dilute the acid enough, it might work.

There are cheaper versions of peristaltic pumps. I built one myself similar to this one:

Amazon.com: Pump Supplies - G728-1 Miniature Peristaltic Self-Priming Pump Small Circulating Pump 100-240V(22～85ml/min(G728-1-2)) : Industrial & Scientific

Buy Pump Supplies - G728-1 Miniature Peristaltic Self-Priming Pump Small Circulating Pump 100-240V(22～85ml/min(G728-1-2)) on Amazon.com ✓ FREE SHIPPING on qualified orders

www.amazon.com

Out of these parts:

https://www.amazon.com/dp/B07GP72BWV

https://www.amazon.com/dp/B08SCK9THN

what type of tubing did you use?

 

[aztodd]

It won't work.

not arguing with you, but I would like to understand why it wont work so that I can learn something new.

 

[Dirk]

See? Only three words!

Ha, you read that post too soon! Just foolin' around.

The pump parts on my IntellipH that come in contact with the acid need periodic replacing. These are parts specifically designed for acid, and they still can't withstand it. I can't imagine a small drip system designed for water, for indoor use no less, is going to do the job. But that's not even the real issue.

Unless you're willing to have acid dripping directly into your pool, you know, like onto your kids' heads, you want to be able to inject the acid into the pool's plumbing system, probably back at the pad, while your main pump is running. The unit you're looking at looks to be designed to drip some water into the air (in essence), with no back pressure. To inject acid into your pool's plumbing, the pump has to be able to overcome your plumbing's pressure, and then some. Plus, you'd need the injector itself. And if you want to do this safely, you'll want some additional safeguards, like flow sensing and/or current sensing. Plus the acid tank itself.

On the off, off chance your little pump could do the job, and be able to last more than a few days, yes, you could save some money, but not as much as you think when you add up everything you'll need. You'd be better off buying something made for the job. And that wouldn't be an IntellipH, by the way, because Pentair's IntellipH requires you also have a Pentair IntelliChlor SWG installed. So you're looking at a Stenner solution, maybe, or something like what @mas985 suggested.

There's nothing wrong with a DIY solution, you just have to consider all the spec's carefully.

 

[mas985]

First, only peristaltic pumps are inherently chemical resistant due to the design and the pump tubing (silicone) and therefore should be the only type of pump you use with chemicals. Sometimes peristaltic pumps are used in aquarium systems but not always so you cannot be sure unless they specifically state that the pump is chemical resistant. But I suspect the pump you posted is not a peristaltic pump.

The tank tubing (to/from the pump) can be PCV clear vinyl although they will cloud up some. Polyethylene is another choice but a bit stiffer.

 

[proavia]

Work on getting your TA down to about 60-70. That will help slow the pH rise. With our high TA fill water, it will be a bit of a challenge. Keep your pH around 7.5, based on your CH of 500 and the PoolMath computed CSI. Keep the CSI slightly negative (0.00 to -0.30) to minimize scale.

I add acid once, maybe twice a week now that my TA is in the 60-70 range.

As for the device you listed - chances are high it won't work, as it's not made to run chemicals thru. As @Dirk mentioned, you possibly could make it work, but needing to add/replace with quality chemical parts would drive the cost way up.
Install a quality acid dosing system - do it right and only need do it once.

 

[aztodd]

See? Only three words!

Ha, you read that post too soon! Just foolin' around.

The pump parts on my IntellipH that come in contact with the acid need periodic replacing. These are parts specifically designed for acid, and they still can't withstand it. I can't imagine a small drip system designed for water, for indoor use no less, is going to do the job. But that's not even the real issue.

Unless you're willing to have acid dripping directly into your pool, you know, like onto your kids' heads, you want to be able to inject the acid into the pool's plumbing system, probably back at the pad, while your main pump is running. The unit you're looking at looks to be designed to drip some water into the air (in essence), with no back pressure. To inject acid into your pool's plumbing, the pump has to be able to overcome your plumbing's pressure, and then some. Plus, you'd need the injector itself. And if you want to do this safely, you'll want some additional safeguards, like flow sensing and/or current sensing. Plus the acid tank itself.

On the off, off chance your little pump could do the job, and be able to last more than a few days, yes, you could save some money, but not as much as you think when you add up everything you'll need. You'd be better off buying something made for the job. And that wouldn't be an IntellipH, by the way, because Pentair's IntellipH requires you also have a Pentair IntelliChlor SWG installed. So you're looking at a Stenner solution, maybe, or something like what @mas985 suggested.

There's nothing wrong with a DIY solution, you just have to consider all the spec's carefully.

Ah ok got it - this all makes sense. It's enlightening that even the systems designed for acid injection require regular part replacements. If IntellipH isn't an option (without also replacing my swg) then what other recommended non-DIY (or easy DIY) options are out there for acid injection/dosing?

 

[mas985]

This is really cheap but not much control.

Homemade Acid OR Chlorine Injection System

Having a plaster pool with a SWG and fill water with high PH and TA has meant a constant battle with rising PH. I have tried the borax route with lowered TA but because of the high TA fill water, I haven't had much success in lowering my acid use. So I decided to look into acid injection...

www.troublefreepool.com

 

[Dirk]

Ah ok got it - this all makes sense. It's enlightening that even the systems designed for acid injection require regular part replacements. If IntellipH isn't an option (without also replacing my swg) then what other recommended non-DIY (or easy DIY) options are out there for acid injection/dosing?

Yah, we'll have to rely on others chiming in, because all I know is IntellipH. When others talk about alternatives to IntellipH, the brand "Stenner" always comes up. Check out their website for their offerings. Or google "Stenner Acid Pump" and you'll get a bunch of online pool parts vendors that sell them.

 

[Dirk]

even the systems designed for acid injection require regular part replacements

Seems like they should be tough enough, right? But think about it. To adjust my pool's pH several points, I only use about a half a cup of acid. That's a half of one cup, in 12000 gallons of water! Pool acid is definitely some strong stuff!

 

[mas985]

I dilute my acid 4:1 and just refill more often. It is easier on the equipment.

 

[Lake Placid]

Commercially I used Stenner pumps for ph management. We’d pull 20° MA directly out of 15 gallon drums with them. I can attest to the pumps use-ability, longevity and durability. I can’t speak for an out of the box stenner solution though as I’ve never used one. Our Intelliph systems actually do use stenner pumps in them, just smaller ones on a pentair branded tank.

 

[guinness]

There is also the Hayward pH Dispense Acid Feed System that can be used with with any on/off controller or automation system.

Hayward Chemistry Kit 4 - pH Dispense for Acid Feed

 

[Dirk]

There is also the Hayward pH Dispense Acid Feed System that can be used with with any on/off controller or automation system.

Hayward Chemistry Kit 4 - pH Dispense for Acid Feed

Interesting, I didn't know Hayward had an offering. Also interesting... they must have all had some sort of clandestine arrangement, because they all seem to be suspiciously close to the same price (Pentair, Hayward, Stenner).

From the looks of it, only Pentair's IntellipH requires their SWG be present. The IpH monitors the IC, and uses the IC's built in temperature and flow sensors to allow or disallow acid dispensing, so it's a mixed blessing: you have to have an IC, but the IC is supplementing extra safeties. I don't know if either the Hayward or the Stenner have comparable safeties built in.

The IntellipH piggie backs off the IC's power supply, so there's that (that's the main reason the IC has to be present). Is that an advantage or disadvantage? If the IC is wired correctly, it can't run without the main pump running, so neither can the IpH. So that's another safety that you'd have to recreate with the other offerings (by how they get wired in to the controller).

There's actually a lot going on "behind the scenes" when automating acid dispensing, and a lot to understand/consider/recreate if you're going to DIY and want it done correctly and safely.

 

[TexEdmond]

Hey, Todd, welcome to the crew. I find myself in a nearly identical situation, and unfortunately I've not been able to find a cheap / safe / effective automated option, but I can report I'm still using that same old 20oz gatorade bottle and it hasn't disintegrated yet, after however many gallons of acid I've poured into and out of it.

You might consider a gravity fed dosing option just to save you a little bit of time, but that's not what I've found myself doing. It's a minor hassle but with the in-floor cleaners, robot, and SWG, if I've got to do 6 minutes of pool maintenance every couple of days, so be it. For what it's worth, with all of the continual aerating on my pool, even dropping TA down to 60 hasn't helped much; I'm always at a CSI of +0.3 or higher every 48 hours no matter what. Really my last option is to try adding borates so my CSI stays negative even when the pH gets up over 8.0.

Poor man's IntelliChem

EDIT: Read thru this thread first before building anything resembling my first prototype... there's better and safer options. I've been putting so much muriatic acid in the pool lately, I decided to get lazy. I was using a 20oz "gatorade type" sports drink bottle to measure out and slowly...

www.troublefreepool.com

 

[Dirk]

but I can report I'm still using that same old 20oz gatorade bottle and it hasn't disintegrated yet

I don't know the chemistry behind it all, but hard plastic, like your Gatorade bottle or most of the components of my acid dosing system, hold up fine. It's the soft stuff that succumbs, like the o-rings in my injector, and the pliable tubing in my peristaltic pump.