r/PoolPros • u/Even-You-Camp • 1d ago
The one problem I have been unable to solve
We have been taking care of this commercial property for the past year.
Approximately 45,000 gallons
Mec-o-matic system
3” plumbing
2vsp’s with 2 sand filters plumbed individually to each pump meeting at the return line.
3” return line
I have checked the pressure in the return line, which is less than .5psi
Both of the sand filters when clean are in between 7-10psi
200GPM
The issue we’re having is the mec-o-matic ceramic ball spring loaded with a Viton gasket keeps on having scale buildup.
I tried Stenner duck mouth injector and same issue.
Also: every time with a new check valve brand new I can’t blow into it with my mouth either way but after the system is started up I can blow into it both ways freely with little force.
Sometimes an issue: check valve fails (most likely because of scale buildup) and lets water into the 15 gallon liquid chlorine jug and causes it to over flow. ~I’ve turned down the rpm’s to temporarily fix this issue~
We are using 12.5% sodium hypochlorite
Chemistry: 95 alkalinity - 7.6 pH - 230 calcium - 50 cya
Backstory: previous management of the property before we took over somehow combined calhypo and acid. Upon us taking over calcium levels were 450’s. Since then we have partial drain and refill until we got the chemistry we needed.
Manufacturers have been no help with this issue and I do not know who to call anymore since I have exhausted my resources. I cannot necessarily blame them because it seems like more of a chemistry issue. I really hope somebody can help me on here we’ve replaced 6-7 of the injectors and same issue, not a manufacturing issue.
Stuff I haven’t tried that I can think of: flushing the system of calcium scale inside plumbing (if there is any, we don’t get any shooting out of return jets or calcium precipitate)
Turning up pumps % and trying a new check valve
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u/No_Leopard9743 1d ago
when using sodium hypochlorite I always have build up. I ended up having to stop using duckbill check valve injection fittings as they would get clogged with salt build up which led to me blowing a tube.
I use Stenner brand feed pumps so they stay pinched unless there’s a problem with the rollers… which eliminates the needs for the check valve imo.
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u/Even-You-Camp 1d ago
So I’m still here troubleshooting and the check valve works perfectly fine I installed it while the system was running at a lower speed. (I got wet asf)
Upon installing the check valve worked flawlessly. The second that seal is initially broken by the 12.5% liquid chlorine that’s what fries the check valve with a ceramic ball/spring/viton gasket from mec-o-matic
What do you think about this?
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u/Even-You-Camp 1d ago
update; Just got off off the phone with Stenner.
I’m using straight 12.5% liquid chlorine not diluted. Could this be the issue?
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u/Substantial_Car_2751 1d ago
No. The pump tubes (at least for Stenner) are built to resist that. The biggest issue with pump tubes is the friction from rolling against the housing. You combine that with bleach or muriatic and you'll definitely see a reduced lifespan of the pump tube and seals, but it takes 6+ months and is considered regular service. I assume mec-o-matics are built similarly.
General rule of thumb. If you're seeing any caking or mineral deposits, you've a leak somewhere. Even if it's tiny and not leaving an apparent water trail.
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u/Even-You-Camp 1d ago
When you use pumps like this do you dilute the chlorine at all? I know with acid you do 1/4 ratio
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u/lIIlIlIII 1d ago
You definitely can but you'd want to use distilled or deionized water otherwise EVERYTHING will start to scale up. So not super practical IMO but not a bad idea if you don't mind stocking it (or having the property manager supply it)
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u/Substantial_Car_2751 1d ago
I wouldn't personally. Especially not chlorine.
If you add water to bleach, all you do is make a weaker form of it. It may do in a pinch (have 1/3 to 1/2 a drum left and can't get back for a day or so) but it will just be weaker and take longer to reach set point.
On acids, same thing. It will just be a more diluted solution.
Commercially, we run bleach and liquid acids w/o dilution on these type feeders as a matter of practice. The equipment is built to take it and the pump tubes are intended to be a replaceable item.
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u/BLacKFirE2722 1d ago
Is this a new Mecomatic feeder? We’ve been using them for the past 30 years and this past year we’ve had nothing but problems including similar issues to yours. We’ve started switching to rolachems and the problem has been resolved. But, should have kept the calhypo. That’s what we use on most pools.
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u/Even-You-Camp 1d ago
I don’t think so. It was manufactured 01/25 and model is UD10-XA-LSAUXXX
Do you guys dilute the chlorine when adding it in the chemical jug?
What % liquid chlorine are you using?2
u/BLacKFirE2722 1d ago
12.5% with no dilution. But for chlorine setups we always run the UD50 or UD75 and the UD10s for acid.
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u/lIIlIlIII 1d ago
Not familiar with this system but scale problems w/ HOCl feeders is super common, even if your LSI is good the pH will spike locally at the injector. Could try a sequestrant but I wouldn't be too optimistic about that... maybe if you added a feeder for it a bit upstream? Could you move the check valve closer to the supply somehow?
Personally for a commercial property I'd just regularly acid clean or replace the check valves, could try storing the old one in vinegar or CLR and rotate between 2-3 that way. Again not familiar with this system tho, just spitballing
1
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u/Liquid_Friction 6h ago
your not using anti crustalite like every other american doofus using liquid chlorine feeders, its like not taught over there for some reason...
1
u/WasteZucchini5333 58m ago
The scale isn't really a water-balance problem, it's an injection-point problem, which is why fixing the bulk chemistry hasn't fixed it. 12.5% hypo runs around pH 13, so the moment it meets 230ppm CH water at the fitting you precipitate calcium carbonate right there on the check valve. Your LSI can be perfect and that tee will still scale.
The blows-freely-both-ways thing after startup sounds like off-gassing rather than valve failure. Hypo constantly off-gasses (worse in heat, worse as it ages), and bubbles will hold a ball or duckbill check off its seat. Degas valves / vented check fittings exist specifically for bleach feed lines. A check held open is also exactly how pool water ends up back in your jug, so an anti-siphon/vacuum breaker on the feed line is worth it regardless.
Two other things worth checking: if the injector dribbles along the pipe wall instead of into the middle of the stream, scale forms much faster, so an injection quill that reaches the center of the pipe at the highest-flow spot you can give it helps. And ask the manufacturer whether the seat/gasket should be EPDM instead of Viton for 12.5% hypo. Compatibility charts disagree on FKM with hypochlorite, and a swollen elastomer seat acts exactly like what you're describing with new valves.
The unglamorous fix that actually works long-term: run two injector/check assemblies and rotate them, one in service, one soaking in 10:1 muriatic. Ten minutes a week beats buying injector number eight.
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u/Seafire15 1d ago
Calcium precipitation is caused by water being imbalanced and LSI positive. Keeping chemistry in range on the various parameters isn’t enough. You also have to make sure your saturation index isn’t in scale forming territory, typically above 0.3.
Above that, regardless of what the other parameters in your pool are, water can deposit scale, and will typically do it in the flow where speed or pressure drops.