Ideal constant water change system

[jeffberens]

I was thinking about creating the best constant (daily) automatic water change system to work with my Apex system.
I know a number of reefers use the Dos pumps to achieve this and I know that they also now make the Pmup pump that can handle a reasonable amount of head pressure.

Would 2 Pmups (1 for draining old water, 1 for pumping new salt water) or the Dos be a better way to go?

 

[mcarroll]

Yes but there are other ways than that particular setup.

You might tune into post #4 on another semi-related thread.

 

[jeffberens]

Yes but there are other ways than that particular setup.

You might tune into post #4 on another semi-related thread.

Not really sure that gives me any further perspective. I have read numerous set-ups with the Dos pumps automated as well as discussions as to how quickly they may burn out if used constantly as well as the fact that they can be noisy.

The Pmup pumps are touted as perfect for ATO scenarios and are substantially less money and quieter.

My question relates to which is the better overall solution for automating and why? Price is not that important of a factor for me.

 

[mcarroll]

Appologies, I thought "pmup" was a typo. Thought you were fielding more general recommendations....APT instruments is what I'd buy if I was buying today. Don't think that helps you though.

 

[p7willm]

It depends on how you want to do it and what the pump was designed to do. The DOS is designed to move very specific amounts of water. Each revolution of the pump head will move a specific amount of water and the DOS counts how many times they revolve. As part of the installation, and maintenance, you run the pump for a time and measure how much water comes out and if the amount is wrong you adjust it in software. So when you tell the dos to move 2 liters of water it does it,

A diaphragm pump will be pretty close but not as exact as the DOS.

I have a DOS, but if I had it to do over I might not use one. It is slow, and noisy (mine is in the basement so it doesn't bother me too much) and, though I can have add just as much as I take out there are other losses of salt like skimmate and a little creep that need to be handled differently. The DOS is also expensive.

I have a conductivity probe that checks constantly and every time I make new water I use a refractometer to check the tank and the new water.

 

[jeffberens]

It depends on how you want to do it and what the pump was designed to do. The DOS is designed to move very specific amounts of water. Each revolution of the pump head will move a specific amount of water and the DOS counts how many times they revolve. As part of the installation, and maintenance, you run the pump for a time and measure how much water comes out and if the amount is wrong you adjust it in software. So when you tell the dos to move 2 liters of water it does it,

A diaphragm pump will be pretty close but not as exact as the DOS.

I have a DOS, but if I had it to do over I might not use one. It is slow, and noisy (mine is in the basement so it doesn't bother me too much) and, though I can have add just as much as I take out there are other losses of salt like skimmate and a little creep that need to be handled differently. The DOS is also expensive.

I have a conductivity probe that checks constantly and every time I make new water I use a refractometer to check the tank and the new water.

So, if you had to start fresh and wouldn't use the Dos, what would you go with?

My main goal is to automate it and make it easy. I do have the Apex and plan on having control of my mixing station. I would be fine with creating and automated option with a couple of virtual outlets to start the drain and then the fill process. If I go that route it would likely be a weekly larger waterchange and I would use a larger/faster pump option.
If I were to go with a Dos or similar option, I would likely have smaller daily or multiple daily water changes.

I appreciate the input about the Dos and it does reiterate some of the concerns I have read about in other threads.

 

[p7willm]

I would have to look around, but I would not require the pump I used be as precise as the DOS. Just get something to get about the same in and out. I would have a salinity probe and if the salinity was low I would add a little extra new water each day.

One problem I have is that the new water and drain are both in the basement so new water has 10' of head and old water has 10' of suction, so I am probably limited to peristaltic pumps.

 

[jeffberens]

I would have to look around, but I would not require the pump I used be as precise as the DOS. Just get something to get about the same in and out. I would have a salinity probe and if the salinity was low I would add a little extra new water each day.

One problem I have is that the new water and drain are both in the basement so new water has 10' of head and old water has 10' of suction, so I am probably limited to peristaltic pumps.

How about a pump in the sump with hard line to the drain and a pump in the basement mixing station to pump new water back up to the sump with a seperate hard line plumbed?

I know I would need valves to be safe (possibly solenoid valves to automate?).

I was thinking of having a float valve to add correct amount of new water and another float valve to stop draining without running the pump dry.

S0,
1. Return, Skimmer, heaters, etc. power off
2. smaller pump in sump starts to drain water to waste from main sump area until low water float valve engages.
3. pump in basement mixing station turns on and pumps new water into sump until high water (resting water level) float valve engages and it stops.
4. Return pump turns back on and after 30 min delay skimmer goes back on.

I'm sure there are some hurdles or flaws in this system. What are they?

 

[p7willm]

Use timers to be sure drain time and fill time are not too long and shut off if either takes too long.

Why do you have skimmer off for 30 minutes after? usually you just wait a couple of minutes for the water lever to stabilize.

 

[reefwiser]

The issue with this is that if you have two pumps they will never both pump the same amount. You would need to use level switches to this.
I use a stenner dual head pump to keep the water input and output the closest I can. The dual head design removes water as in puts water into the tank so water level is not an issue.

 

[jeffberens]

The issue with this is that if you have two pumps they will never both pump the same amount. You would need to use level switches to this.
I use a stenner dual head pump to keep the water input and output the closest I can. The dual head design removes water as in puts water into the tank so water level is not an issue.

Hence in my description the high and low float sensors. It would only drain to the low float and fill to the high float. That way timing and pump pressures don't need to perfectly match. I would just set up my apex to allow slightly longer than needed for each phase before it shuts the solenoid valves just in case.

 

[reefwiser]

I have done it like that in the past. I do this type of work for my job at a large food producer. I have found it to me much simpler to just run a dual head stenner pump eliminating the use of float switches all together. Which can be a point of failure and water on the floor. [emoji3]

 

[jeffberens]

I have done it like that in the past. I do this type of work for my job at a large food producer. I have found it to me much simpler to just run a dual head stenner pump eliminating the use of float switches all together. Which can be a point of failure and water on the floor. [emoji3]

Good advice. That's kind of what I was trying to sort out. I was thinking of doing the DOS for that purpose, but I have heard they are a little loud and they won't end up being perfectly equal with what is added vs removed. I will be monitoring salinity with my Apex as well, but I like the idea of being able to initiate a decent sized water change at any time if need be.

I am now thinking I will run a 3/4 hard line from the sump to a drain and another 3/4 hard line from my mixing station to the sump. I will have the appropriate manual ball valves to initiate a larger water change and do it once a week. Later down the road, I might add the DOS and automate smaller more frequent water changes.
If using a stenner pump or the DOS, is it better to have it located down by the mixing station and pump up to the tank or the other way around and why?

 

[reefwiser]

Here is my beginning set up of the Stenner AWC. I still have to set up the mixing station.
The stenner can push water quite a distance. I let it fill the lines before I did water changes on the tank.

 

[jeffberens]

Here is my beginning set up of the Stenner AWC. I still have to set up the mixing station.
The stenner can push water quite a distance. I let it fill the lines before I did water changes on the tank.

Nice! What is different between the Stenner pump and the DOS? Is that a diaphram pump or a peristaltic pump?

 

[Water Dog]

I've been looking into the Stenner as well. Best part is that it is a peristaltic pump with two heads driven by a single motor, thus it will pull out waste water and put in new water at exactly the same rate without ever drifting volumes. The DOS on the other hand will eventually drift as it is two independent pumps that are calibrated separately that over time, vary from each other.

 

[SethOF]

I've been looking into the Stenner as well. Best part is that it is a peristaltic pump with two heads driven by a single motor, thus it will pull out waste water and put in new water at exactly the same rate without ever drifting volumes. The DOS on the other hand will eventually drift as it is two independent pumps that are calibrated separately that over time, vary from each other.

But the DOS is a peristaltic pump.

The issue of drifting is another matter, though considering the small volumes being exchanged relative to the total tank volume as well as the role top off water for evaporation I doubt that it is significant.

 

[Water Dog]

With automatic water changes, the accuracy of equal volumes is important. I understand that the DOS is a peristaltic pump, however, it is 2 independent heads run by 2 independent pumps which no matter what, will require calibration. The Stenner is an industrial grade pump designed for continuous operation pumping industrial chemicals. Both of its heads are run by a single motor so you will never have to calibrate it. One less thing to have to worry about IMO. As far as I'm concerned, I'll trust an industrial grade pump designed for continuous use over a designed intermittent use dosing pump built for our hobby any day for the purposes of AWC.

 

[reefwiser]

Nice! What is different between the Stenner pump and the DOS? Is that a diaphram pump or a peristaltic pump?

I think the question has been answered [emoji3]
The Stenner is a peristaltic pump with both head driven by one motor. Real simple way of doing a AWC. Where simple is better.

 

[Dubs83]

I use two PMUPs with three float switches. Twice a day, I pump 4 gallons out of the return section to a low point designated by a float switch (Sump_Low). Once that triggers, the water stops pumping out of the sump and I begin refilling sump with fresh water until a designated float switch is tripped (Sump_Normal). Should this ever fail, I have a third float switch (Sump_High) which acts as redundancy.