How many people use a DOS on their calcium reactor
- Thread starter Hausser
- Start date
- Tagged users None
It is a myth that you need a continuous pump for a calcium reactor.
@Terence has been experimenting with running his CaRx with a DOS for the last year or so. You will have to replace the heads because of wear and tear every 6 months or so. By his own admission, a hobby grade pump will never compare to an industrial grade variable speed peristaltic pump in terms of reliability and longevity. Some details of his set up and rationale can be seen in this Watson Marlow peristaltic pump thread...
https://www.reef2reef.com/threads/watson-marlow-peristaltic-pumps-for-calcium-reactors.289356/
That said, I have a Watson Marlow 505s for my CaRx.
https://www.reef2reef.com/threads/watson-marlow-peristaltic-pumps-for-calcium-reactors.289356/
That said, I have a Watson Marlow 505s for my CaRx.
Glad you said it! When I say it, people go nuts.
This is mostly because a. people do not really understand how a calcium reactor works - it is mysterious. and b. People generally are not good at math. Sprinkle in a bit of anecdote and you have the ingredients for a myth.
Radman73
Valuable Member
It's just another way of DOSing something. It can be done constantly, which does have certain benefits, or periodically.
Do you mind expanding on that pls?
It's really just a math problem.
What are your variables:
Flow rate in/out: usually around 50ml/min
pH set point: usually around 6.75
Aquarium pH: say 8.0
CaRx Volume: say 20L (20,000ml)
Duty Cycle: 3:1
Now look at those numbers and if you need to, do the math. You are putting 150ml of water with a pH just 1.25 units lower into a volume of water that is over 100x. Again, not doing the math, but even if you lowered the pH 2% in a particular scenario, that is insignificant in terms of creating any kind of crazy oscillation. Also, that assumes all 150ml went in at once, which it does not.
If you want a better reason to go with an industrial pump for this purpose, I would say it is the durability side.
Now, crazy at it sounds to most that know me, I am not going to try and sell you something here. Instead, I am going to give you a better idea for how to run those masterflex style pumps with your Apex. Now that you see it makes no difference, instead of running them just "ON", create your own duty cycle. Why? Because this will allow you to fine tune your output of the pump itself right from your phone.
What are your variables:
Flow rate in/out: usually around 50ml/min
pH set point: usually around 6.75
Aquarium pH: say 8.0
CaRx Volume: say 20L (20,000ml)
Duty Cycle: 3:1
Now look at those numbers and if you need to, do the math. You are putting 150ml of water with a pH just 1.25 units lower into a volume of water that is over 100x. Again, not doing the math, but even if you lowered the pH 2% in a particular scenario, that is insignificant in terms of creating any kind of crazy oscillation. Also, that assumes all 150ml went in at once, which it does not.
If you want a better reason to go with an industrial pump for this purpose, I would say it is the durability side.
Now, crazy at it sounds to most that know me, I am not going to try and sell you something here. Instead, I am going to give you a better idea for how to run those masterflex style pumps with your Apex. Now that you see it makes no difference, instead of running them just "ON", create your own duty cycle. Why? Because this will allow you to fine tune your output of the pump itself right from your phone.
How long will a DOS last you? What are the replacement head costs. Better imo to pick up a used continuos duty peristaltic pump off eBay regardless of whether you run it continuously or not. Better to use the right tool for the job. I would use a controller to control a true continuos duty pump to dose when consumption is highest during the day or night. People using alk monitors are finding that consumption changes through the day. I agree with @Terence in using the Apex to control the pump just wouldn’t use my DOS for it. Now if Neptune came out with a continuos duty pump for Calcium reactors I’d be all over that.
Last edited:
There are reasons to do it either way. On the DOS side you get something that is arguably easier to set up and use. On the industrial side, you get more longevity before maintenance (I think - I am not a user of one of these).
For the DOS, the heads are rated at ~750 hours MTBF - that includes the mechanics as well as the peri-tube. Replacement cost is $30 and it is super simple to change out compared to other methods I have seen.
Now while that is the rating, I personally have put far more time and water through these. The official number is above. My number is much higher. YMMV.
Both of these methods are quite noisy for the average hobbyist with a larger tank/demand that requires a higher flow rate. Because of this, soon I think I may try something even more controversial - using one of our PMUPs to drive my calcium reactor with it valved down to maybe half output using a bypass. Then, I will adjust the duty cycle to get the flow rate I want through the reactor. We will see...
For the DOS, the heads are rated at ~750 hours MTBF - that includes the mechanics as well as the peri-tube. Replacement cost is $30 and it is super simple to change out compared to other methods I have seen.
Now while that is the rating, I personally have put far more time and water through these. The official number is above. My number is much higher. YMMV.
Both of these methods are quite noisy for the average hobbyist with a larger tank/demand that requires a higher flow rate. Because of this, soon I think I may try something even more controversial - using one of our PMUPs to drive my calcium reactor with it valved down to maybe half output using a bypass. Then, I will adjust the duty cycle to get the flow rate I want through the reactor. We will see...
I have two Masterflex peristaltic pumps running for years in my calcium reactor and for dosing vinegar. These were purchased at ebay for under $100. Nothing better for continuous operation and reliability.
No argument there. Great product. $100 though is a steal. Don't think you can do that anymore.
Yes you can. Just create a search "Masterflex pump" and with some patience you will find one. Right now there is one for $49 without the head. "Cole Parmer easy load Masterflex Precision Pump"
That sounds like a smokin deal! How much is a new head?
Similar threads
