Check Valves

[Integral9]

So last night I checked my kalk stirrer and the over 1/2 the kalkwasser was empty. After some hmm'n and ha'n, I figured out that my check valves on my peristaltic pump had failed and it was back siphoning back into my resevoir. do'h! So I've removed the straw on the kalk stirrer to break the siphon, but it's a less than optimal solution as some less concentrated kalk will be dripping into my tank now. So I need new check valves.

 

Now I remember buying those check valves not even a year ago, so I am a little miffed about this. I got them at Petsmart and since the selection of check valves there was not all that great, I went with the top fin brand they carry. The type with a clear bottle and a little rubber wedge shaped stopper. Apparently a bad choice.

 

What kind of check valves do you guys use for your dosing? Do you like em? How long have you had them? Where'd you get them?

 

Thank you.

[dbartco]

I have had too many of them fail over the years (john guest, silver dollar shaped white ones, top fin and others like that, even the expensive $17 Dernele (sp?) ones), so I went to putting a siphon break "T" in the line, running one leg above the tank, and the other feeding the stirrer.

 

(granted I have the built in so I can hide behind the tank)

[epleeds]

I have had too many of them fail over the years (john guest, silver dollar shaped white ones, top fin and others like that, even the expensive $17 Dernele (sp?) ones), so I went to putting a siphon break "T" in the line, running one leg above the tank, and the other feeding the stirrer.

 

(granted I have the built in so I can hide behind the tank)

 

got pics?

[STEVE]

As Doug mentioned...I too have tried several different one's, only to have them all fail...I am following this thread.....

 

 

[Origami]

You have a check valve on a peristaltic pump? How did the pump fail? The rollers normally keep a peristaltic pump closed when not pumping (when the rollers aren't turning).

[dbartco]

Really, thankd Dave lin for telling me this. The MJ does not have enough head to get the water that high, and when the water drops with the pump off, the air will break the siphon.

 

[GraffitiSpotCorals]

I used the kind that snaps on RO tubing. It lasted a good year and a half. It broke while on vacation (luckily the only thing that went wrong!) and have been thinking about doing the setup like that because I am also tired of them failing.

[Ryan S]

the only check valve i have ever used is a george fisher wye check valve. expensive, but it's never failed me.

 

http://www.bulkreefsupply.com/george-fisher-wye-check-valve-1.html

 

i don't think this is the type you're looking for though.

[STEVE]

I have the Tunze ATO and that pump WILL have enought power to flow to the top of the tank....

[Integral9]

I have had too many of them fail over the years (john guest, silver dollar shaped white ones, top fin and others like that, even the expensive $17 Dernele (sp?) ones), so I went to putting a siphon break "T" in the line, running one leg above the tank, and the other feeding the stirrer.

 

(granted I have the built in so I can hide behind the tank)

 

Unfortunately, I don't think my peristaltic pump can self prime, so if the siphon breaks past the pump it will not work at all.

 

You have a check valve on a peristaltic pump? How did the pump fail? The rollers normally keep a peristaltic pump closed when not pumping (when the rollers aren't turning).

 

Yup, I have 2 of them actually; one right before and one right after. I'm not sure where I read this, but I thought you needed to have them to make sure you don't loose prime on the pump. But you are right in that the rollers will keep it closed, but my pump only has 2 rollers and if it stops at the wrong spot, it will leave the line open, slightly. The pump is a SP3000. The "squidy" (tube the rollers go over) is about as old as the check valves and it looks like it's still in good shape.

 

the only check valve i have ever used is a george fisher wye check valve. expensive, but it's never failed me.

Thank you, but those are too large. I need something for 1/4" line.

 

Thanks for the info guys. It appears I need to look outside the hobby for something better. So it seems that all the check valves I can find from the aquarium stores are all some kind of passive design. Either a wedge that moves w/ the water or a diaphragm. So I am going to look for a spring loaded design. IIRC, When I built my K1 at the build party, the guy from Avast (sorry, forgot his name) mentioned that he had to use nylon inside the Kalk stirrer because PVC didn't react well to the high alkaline environment. With that in mind a nylon check valve would ideal just in case the valve fails again and kalkwasser back flows into it. Also, there is something better / more heavy duty than the typical rubber (Buna) stops / seals in typical check valves and it's called Viton.

 

I found this and ordered a pair:

http://www.sustainablesupply.com/SMC-WNCHK695-4B4B-F-Spring-Check-Valve-1-4-In-Ba-p/w169009.htm

$4.91 Spring Check Valve, Ball Cone Design, Material of Construction White Nylon, Size 1/4 In., Barb Connection, Length 2.02 In., Width (In.) 0.50, Overall Height (In.) 0.50, Rated For 125 PSI, Cracking Pressure (PSI) 1, Max. Temp. (F) 140, Seat Material White Nylon, Spring Material Stainless Steel, Seal Viton

 

I guess I'll see how they do.

 

fwiw: That website has a plethora of check valves if anyone is interested in other designs.

[Origami]

Yup, I have 2 of them actually; one right before and one right after. I'm not sure where I read this, but I thought you needed to have them to make sure you don't loose prime on the pump. But you are right in that the rollers will keep it closed, but my pump only has 2 rollers and if it stops at the wrong spot, it will leave the line open, slightly. The pump is a SP3000. The "squidy" (tube the rollers go over) is about as old as the check valves and it looks like it's still in good shape.

You don't need a check valve on a peristaltic pump. They work on a vacuum principle using the rollers to pull the fluid along in the direction of the roller travel. It's sort of like milking a cow - sorry, I'm sure we all have a lot of experience with that! (My dad grew up on a farm and there were stories growing up....) Anyway, they're self priming.

[Origami]

Sorry, I just read that you had two rollers, not four or more. I see the problem now. What brand is this pump anyway?

 

Put a siphon break (long upright tee) on the downstream side of the pump. This will fix the problem and last longer than a check valve.

[Integral9]

It's a AquaMedic SP3000. Also, I don't think it's self priming. When i first set it up, it started to suck the water up the line to the pump, but after 5-10m of me sitting there watching the water level bounce up and down in the tube, I decided it wasn't going to self prime and primed it myself.

 

I just read the manual and it says it's self priming. I disagree.

[Origami]

Do you have the right tubing installed? (Both outside and inside diameter will be important.) Is the tubing installed correctly? (Is there a guide of some sort missing that would keep at least one roller engaged at all times?) Either could be a problem.

[Origami]

If this is original Aqua Medic tubing, the walls on it may have lost their resiliency and may be permanently compressed. In this case, it may not have enough spring to pinch off the tubing as the roller passes by. Tubing does wear out. I have a variety of tubing here at home, if you had some sort of measurements on your tubing (ID, OD & length), I might be able to find a match.

[hlem]

Here is my ATO. never get siphon from the Kalk stirrer. If the aqualifter pump fails, it'll just suck back air. two float valves, one in sump, one in the water reservoir. First float valve is for RO/DI unit, and not the from Kalk stirrer. Kalk stirrer water is gravity fed into the water reservoir. RO/DI unit is conntected to an auto shut off valve.

 

Edited November 14, 2012 by hlem

[dbartco]

I have the Tunze ATO and that pump WILL have enought power to flow to the top of the tank....

 

would only be the case if for some reason the line was clogged through the kalk reactor. I have never had that happen. If it did, I would just have a waterfall. Maybe out in a p'n cherub or something.

[hlem]

sorry, gave a second look and realized I was mistaken

 

this design is very hard to fail. it would require that the auto shut off from the RO/DI unit to fail and both float valves to fail, all at the same time.

[Integral9]

If this is original Aqua Medic tubing, the walls on it may have lost their resiliency and may be permanently compressed. In this case, it may not have enough spring to pinch off the tubing as the roller passes by. Tubing does wear out. I have a variety of tubing here at home, if you had some sort of measurements on your tubing (ID, OD & length), I might be able to find a match.

 

I'm not sure what the size is. I'm still looking around the interwebs for it though. Must be one of those industrial sekrets because buying that stuff @ $2/ft wouldn't fair, so instead you pay $36 for 6"...

 

This is the product though.

http://www.marinedepot.com/ps_viewitem.aspx?idproduct=AQ4611&child=AQ4611&utm_source=adwordsfroogle&utm_medium=cse&utm_campaign=adwordsfroogle&utm_content=AQ4611&gclid=CMj41OGNz7MCFU-d4Aodpw8AsA

[Integral9]

A guy on RC said the Outside Diameter is 7/16. So ID is probably 5/16. At least that's the standard ID size that matches the 7/16 OD I'm seeing around the internet.

[Origami]

I did some searching, too, and found the same RC link. That makes it similar to Cole Parmer's LS/18 tubing. Unfortunately, the tubing I have is either 3/8" or 1/2". I have both in Norprene, my preferred tubing for peristaltic pumps. If you think that you could make either work, I'd be more than happy to cut off a length for you to give it a try.

[davelin315]

Solve your problem by adding an airline check valve to the top of the line in the T.

 

If you add the airline check valve to the tube at the top, it won't ever fill up with water since the air is prevented from exiting the tube. When your pump turns off, it will allow air to be sucked in through the siphon created by the line and it will break it. Easy to make, works like a charm, never had a siphon occur with this design. Only thing you'll need to do is periodically check the tubing and ensure that you have a tight connection so that it doesn't come apart.

[Origami]

Solve your problem by adding an airline check valve to the top of the line in the T.

 

If you add the airline check valve to the tube at the top, it won't ever fill up with water since the air is prevented from exiting the tube. When your pump turns off, it will allow air to be sucked in through the siphon created by the line and it will break it. Easy to make, works like a charm, never had a siphon occur with this design. Only thing you'll need to do is periodically check the tubing and ensure that you have a tight connection so that it doesn't come apart.

If I'm reading his situation right, this will allow his tubing to drain and he'll lose prime. Fundamentally, he's got a peristaltic pump that is not sealing at at all times the rollers. In certain situations, when the pump turns off, neither roller is pinching off the tubing and he's got a siphon that results. If the siphon were to break, the tubing would be drained from end to end and, apparently, he needs to re-prime the line to get it working again.

 

For me, the right course is to get the pump working the way it's supposed to. That is, with the rollers pinching off the tubing. Once that happens: No siphoning; and no issues with getting the pump to work as intended.

[extreme_tooth_decay]

FYI:

 

I have the exact same pump and the exact same issue. In my case, it is even more of a problem for the tubes to lose the water because the outflow from my pump goes up 10 feet to the next floor. That pump's spec sheet specifically states that if the rollers stop the wrong way, this problem will occur

"If the pump stops with the drive axle in the horizontal position then the pump will not act as a non return valve."

That is just how this pump is designed. Replacing your hose will not address this. (Side note: Mine came with an extra hose, did yours?)

 

I have been using a RENA "Deluxe Airline Check Valve" for many years and have not had a problem.

 

Like this one: LINK

 

Your results may vary, greatly...after all, it is a cheap piece of plastic.

Edited November 15, 2012 by extreme_tooth_decay

[Origami]

Thanks for that, Tim. It's too bad it doesn't have more rollers to prevent this situation from occurring. A check valve and a siphon break (in case the check valve fails) may be the only way to really address this for this pump.