Watson Marlow Peristaltic Pumps for Calcium Reactors

[louisvillereefer]

How loud is the Watson Marlow 520s pump? The non brushless Cole Parmers are quite noisy.

I think that all Watson Marlow pumps are brushless. Mine is pretty quiet. My gyre and return pump are much louder than my CA reactor pump.

 

[Breadman03]

How loud is the Watson Marlow 520s pump? The non-brushless Cole Parmers are quite noisy.

I have a 505u, which is an older model, and it is effectively silent. The only "issue" with mine is that it didn't come with a cover for the pump head and would be a safety issue if it were accessible to children or animals. Mine is in my basement and located effectively behind my sump and high enough that kid hands won't find it. I forget what I paid for it, but I think it was in the $3xx range and I didn't really shop around much for it. I just spent a day or so browsing Ebay.

 

[wangspeed]

This post inspired me to look for a Watson Marlow 520. I found a 520du at a great price. Don't really need the ability to calibrate from the other models. Noise is a big concern for me on these industrial pumps and the videos I found of this are very quiet at low RPM.

 

[louisvillereefer]

This post inspired me to look for a Watson Marlow 520. I found a 520du at a great price. Don't really need the ability to calibrate from the other models. Noise is a big concern for me on these industrial pumps and the videos I found of this are very quiet at low RPM.

Great to hear that we have another Watson Marlow fan!

 

[Mattres]

So my follow up question, is why are all these pumps 1K plus, why cant i just get a pump that comes with the dastaco, or something like that? are those too, just stepper motors?

The IKS Vario blue II is a popular continuous use adjustable pump. Quite a lot of people in Europe and here in Australia use them for calcium reactors.
The Dastaco looks like it uses it or a variation of it for their system. It's about $180 Euro

 

[NeverlosT]

I use a brushed cole palmer (masterflex) and man is it loud, great pumps but it is in my living room and it is just too noisy even when boxed up with soundproofing.

Maybe I'll consider one of these as an alternative. Great thread.

Regarding the posts on DASTACO and pacificsun and the DOS, those are all stepper motors and not rated for years of continuous use. Terence mentions that he is using his as sort of an experiment (and he works for the company...). I was told by Pacificsun that their motor was designed for continuous use, and I am sure that dastaco would say the same, but for the money, you are better off with a reliable GEO CARX and a pump designed for medical/lab use for decades, and at a lesser price for the combo. (in my opinion).

Thanks for posting your details!

 

[2una]

I think the dastaco one is brushless rather than stepper as it don't make no noise compared to a DOS.
Supposed to change the internal tube every 6 months or if you have problems they'll tell you you should have.
Mines just over 1 year & had pump problem but i think it was because i put too fine a media in the 2nd chamber & after it compacted i was pushing its pressure/bar limits,lowering the pump & changing the internal tube sorted it out,since gone to something a bit coarser in no2 chamber(seachem md)

 

[wangspeed]

Whoah. I just got my Watson Marlow 520du in. It feels like it's made of lead! It's 20lbs or so. A far cry from hobby grade pumps.

Thanks @louisvillereefer for posting the accessories links. I'll be ordering those too, since mine did not come with the tubing.

 

[ReeferBud]

Why is the assumption made that a continuous effluent rate is necessary?

Why could the same volume not be dosed at separate times in predetermined intervals?

 

[mcarroll]

I'd call it tradition more than assumption.....it works. And I've never heard of anyone running a "batch CO2 reactor"....it might not work, or not work as well, or have complications, etc.

 

[Terence]

The idea that you need continuous, uninterrupted flow for calcium reactors is a myth. That much I have proven. If you did the math you would understand why.

Now, as far as what pump to use, these are all fine choices. The DOS has its positives and negatives in this application and at this point of testing I am not yet going to give a recommendation but it certainly it is serving me well for almost a year. The ability to fine tune the flow from my phone is a huge deal for me - especially when used in conjunction with four automated alkalinity tests a day.

 

[Water Dog]

The idea that you need continuous, uninterrupted flow for calcium reactors is a myth. That much I have proven. If you did the math you would understand why.

Now, as far as what pump to use, these are all fine choices. The DOS has its positives and negatives in this application and at this point of testing I am not yet going to give a recommendation but it certainly it is serving me well for almost a year. The ability to fine tune the flow from my phone is a huge deal for me - especially when used in conjunction with four automated alkalinity tests a day.

I'm doing research on setting up a CaRx for my next build. Been doing a ton of research on manifold setups, Spectrapure's variable speed ATO pump, Watson Marlows, Masterflexes, even GEO's future offering. Your statement and experience clearly challenges the advice and experiences of people running calcium reactors in the many threads I've read, seeking advice for reliable, stable setup and operation.

While making the numbers work on paper is one thing (of which I do not yet have a handle on), practical application is another. Can you further share with us how you came up with your conclusion and how it's applied?

 

[Breadman03]

I'm doing research on setting up a CaRx for my next build. Been doing a ton of research on manifold setups, Spectrapure's variable speed ATO pump, Watson Marlows, Masterflexes, even GEO's future offering. Your statement and experience clearly challenges the advice and experiences of people running calcium reactors in the many threads I've read, seeking advice for reliable, stable setup and operation.

While making the numbers work on paper is one thing (of which I do not yet have a handle on), practical application is another. Can you further share with us how you came up with your conclusion and how it's applied?

I think the issue is that they need stable flow through the reactor over a period of time, but not necessarily at every moment in time.

 

[Terence]

One of the biggest issues with a CRx is clogging on the output. This is especially exacerbated when pumps are used to pull-from rather than push through a reactor.

Also, while not continuous, my method never pauses more than just over 2 minutes. When it does flow, it does so at a rate that will be very hard to ever have a clog. So there is one of the first myths busted - that non-continuous flow will lead to clogging.

Next is continuity of pH in the reactor. Clearly if you are stopping and starting the effluent, the pH in the reactor will be bouncing all over the place and maybe not ever be able to recover in time before the next pump operation. Nonsense unless the intervals were maybe over 10 minutes.

Think about it this way. The volume of most CRx is over four liters and certainly the average is likely in the six liter or more range. And, the volume of the reactor is usually always sized in proportion to the tank and the drip rate similarly so. All in similar ratios regardless of tanks or CRx size, right - for the most part.

Now, do the math. Let's say you have a reactor of six liters. Your effluent rate is 60ml/min. Your "dose" rate is 180ml every three minutes. Your tank pH is 8.0 and your CRx pH is 7.00. You basically just added 180ml of fresh 8.0 pH to a 6000ml volume of 7.0 pH. How much is the pH going to rise. Not much at all. In the image below you can see that my pH in my reactor is pretty stable - it is programmed to be 7.00-7.05. The jump you see in the historical is me changing the set-point up to raise the melt point a bit.

 

[Water Dog]

I have seen someone using a similar "on / off" approach over on RC with the new Spectrapure variable speed ATO pump, cycling on for 12 seconds and off for 8. With a 5 year warranty on the Spectrapure pump, I guess it's not a bad option to run intermittently. I guess time will tell on the wear and tear and longevity of the Spectrapure or DOS pumps vs an industrial lab grade pump like a Masterflex or Watson Marlow.

 

[Terence]

I think neither the DOS nor the spectrapure nor any other hobbyist solution will compare to those industrial pumps in the longevity department.

The real trade off is size and cost. If one had tons of room and could get a masterflex for $200 I would say go for it. At $600 it looks a little different and certainly at over a thousand retail it is a completely different comparison.

 

[ReeferBud]

Terrence's logic is correct. In a recirculating reactor, where the volume of the recirculating chamber is much greater than the throughput through the reactor, batch-operating with an intermittent dosing schedule should not significantly alter the chemistry inside the reactor at low throughput flows.

Another way to view it, is that if the CO2 dosing is perfectly balanced (as can be achieved with a programmed solenoid), the reactor achieves an equilibrium that is maintained over a low range of throughput. If the reactor does not control pH with a solenoid, the logic does not hold, conce CO2 would be continuously added to the reactor and would decrease the pH.

This same concept is routinely used in industrial chemical plants in which reactors are "parked" or put in recycle mode to pause the operation in the case of a problem that needs to be resolved up or downstream of the unit.

 

[Terence]

If the reactor does not control pH with a solenoid, the logic does not hold, conce CO2 would be continuously added to the reactor and would decrease the pH.

Absolutely correct. I did not even consider this mode of operation as I didn't think anyone really ran a CRx that way any more. Why would you go out and buy a $300 aquarium plants electronically controlled solenoid valve when you can get a good standard one for $100 and put the $200 toward an Apex

 

[Water Dog]

Terrence's logic is correct. In a recirculating reactor, where the volume of the recirculating chamber is much greater than the throughput through the reactor, batch-operating with an intermittent dosing schedule should not significantly alter the chemistry inside the reactor at low throughput flows.

Another way to view it, is that if the CO2 dosing is perfectly balanced (as can be achieved with a programmed solenoid), the reactor achieves an equilibrium that is maintained over a low range of throughput. If the reactor does not control pH with a solenoid, the logic does not hold, conce CO2 would be continuously added to the reactor and would decrease the pH.

This same concept is routinely used in industrial chemical plants in which reactors are "parked" or put in recycle mode to pause the operation in the case of a problem that needs to be resolved up or downstream of the unit.

Quite frankly, in all of the research that I've done on calcium reactor operation, this is the first time I've heard of anyone using a non continuous use timed dosing pump to feed a calcium reactor. I find the information quite enlightening.

In essence, what I'm inferring in these last few posts is that although preferred, a continuous duty variable speed dosing pump is not necessary to run a calcium reactor. In fact, if you have a simple pH controller and a traditional dosing pump, you can run a calcium reactor successfully... interesting. Do you run your calcium reactor this way?

 

[Terence]

I do, have for about a year, you can read details in my build thread below.