Who are you asking? If you are asking me in regards to using the skimmer as part of a continuous water change system, then I would say that I'd engineer the salinity control over time. I wouldn't want to rely on a salinity sensor alone to determine salinity, but a combination of many environmental inputs from other systems (HVAC, ventillator, humidity, etc.), I think it would be pretty straight forward to derive a feedback loop to dial in a safe algorithm for fresh water supplementation.
Wet Skimmate Water Changes?
- Thread starter JMBoehling
- Start date
Who are you asking? If you are asking me in regards to using the skimmer as part of a continuous water change system, then I would say that I'd engineer the salinity control over time. I wouldn't want to rely on a salinity sensor alone to determine salinity, but a combination of many environmental inputs from other systems (HVAC, ventillator, humidity, etc.), I think it would be pretty straight forward to derive a feedback loop to dial in a safe algorithm for fresh water supplementation.
jccaclimber
Member
Gernby, you are the one I was asking. I agree that salinity control by sensor is risky. I think you could get it close over time, I'm just pointing out that it needs to be accounted for, and am curious how other people think the problem is best solved.
Well, I've been thinking about several strategies to control salinity, but won't decide which (if any) I would use until I observe it for a bit. I work from home, so I would monitor everything carefully until I gain some confidence in the solution.
However, here are some are a couple approaches I'm thinking about:
- Mix the new water at a lower salinity than the tanks ... observe resulting tank salinity over time ... adjust mixture until an acceptable range is achieved.
- Meter the discharge rate using an intermediate waste bucket with float switch and solenoid drain valve. Whenever the bucket fills to the float switch, flush the bucket. The number of "flushes" per unit of new water pumped would be an indicator of evaporation. The relationship between flushes per gallon of new water and the need for fresh water would be derived over time.
The controls and data collection would be an extension of my ongoing home automation / nerd project.
Attachments
Last edited:
Gyr
New member
I have used wet skim water changes for years. I feel it is a superior way to do water changes, removing more nasties/gallon than just siphoning. It's easy to do, also. Here is my technique:
I usually mix up 12-15 gallons of fresh saltwater (same Specific Gravity as tank water), unplug my pump from my RODI ATO reservoir and plug a pump that's in the fresh saltwater supply into the ATO switch system. The fresh SW pump then feeds into the last chamber of the sump via tubing that is secured above the level of water in the sump so you don't get any backwash siphoning happening. Then I just run the tubing from the drain in the cup of my skimmer into a 5 gallon bucket and adjust the skimmer until i get a steady drip/thin trickle running out of the skimmer into the 5 gallon bucket. As the water level in the tank drops from the wet skimming, the ATO switch activates and kicks on the pump in the fresh saltwater reservoir until the skimmed off volume is replaced. It takes about 2.5-3 hours to fill the 5 gallon bucket, which I just dump down the toilet when it gets full. This just keeps happening until the fresh SW has all been added to the tank and then I unhook everything, turn the skimmer back down to normal rate, plug the ATO RODI pump back into the ATO switch and I am good to go until the next water change.
This process usually takes about 8 hours, so I only do it when I'm able to be home all day. (I've done it for so many years that I now feel comfortable leaving the house for a few hours at a time, I just empty the 5 gal collection bucket right before I go).
I usually mix up 12-15 gallons of fresh saltwater (same Specific Gravity as tank water), unplug my pump from my RODI ATO reservoir and plug a pump that's in the fresh saltwater supply into the ATO switch system. The fresh SW pump then feeds into the last chamber of the sump via tubing that is secured above the level of water in the sump so you don't get any backwash siphoning happening. Then I just run the tubing from the drain in the cup of my skimmer into a 5 gallon bucket and adjust the skimmer until i get a steady drip/thin trickle running out of the skimmer into the 5 gallon bucket. As the water level in the tank drops from the wet skimming, the ATO switch activates and kicks on the pump in the fresh saltwater reservoir until the skimmed off volume is replaced. It takes about 2.5-3 hours to fill the 5 gallon bucket, which I just dump down the toilet when it gets full. This just keeps happening until the fresh SW has all been added to the tank and then I unhook everything, turn the skimmer back down to normal rate, plug the ATO RODI pump back into the ATO switch and I am good to go until the next water change.
This process usually takes about 8 hours, so I only do it when I'm able to be home all day. (I've done it for so many years that I now feel comfortable leaving the house for a few hours at a time, I just empty the 5 gal collection bucket right before I go).
Gyr
New member
Because I only wet skim during the water change I find that I really don't have to worry about SG changes (8 hours of wet skimming per week doesn't seem to have much impact...I do always check the tank SG before mixing up the fresh SW and on the rare occasions that it has creeped up a little I just mix up a more dilute batch of fresh SW. Since it is being added a little at a time over 8 hours I don't feel the mis-matched SG is an issue.
Here is a post I made years ago when I first started the wet-skim water changes that show the favorable impact on my SPSs http://www.reefcentral.com/forums/showpost.php?p=18281850&postcount=7
Here is a post I made years ago when I first started the wet-skim water changes that show the favorable impact on my SPSs http://www.reefcentral.com/forums/showpost.php?p=18281850&postcount=7
Gary Majchrzak
Team RC
fwiw
fwiw
I still check into this thread every now and then- even though I've moved onward to few to absolutely no water changes. (I maintain Chaetodonts with scleractinians).
Those interested in this might want to research Triton (and related) methods.
fwiw
I still check into this thread every now and then- even though I've moved onward to few to absolutely no water changes. (I maintain Chaetodonts with scleractinians).
Those interested in this might want to research Triton (and related) methods.
I just did a test water change in one of my systems using the skimmer to remove old water as I pumped in new water without any adjustments to the skimmer at all, and it worked even better than I expected! I simply pumped new water into the sump, and let the skimmer overflow into a bucket. It only took 21 minutes to do a 5 gallon water change, and the water level in my small sump is within a quarter inch of where it started. It actually stayed within about a half inch of where it started throughout the whole process.
My goal was to setup an automated continuous water change system, but now I think that it would be better to setup a simpler system that does a daily 0.5 - 1.0 gallon water change over a period of about 30 minutes (at an optimal time of day). With that approach, it would be much easier to control salinity, since the timing of the water change could be coordinated with the timing of the auto-top off to ensure a consistent end state.
Note that the skimmer was running with its pump speed at the highest level before, during, and after the water change. Also note that I replaced the flow adjustment valve on the skimmer outlet (rotating vertical gate valve) with a custom non-valved, fixed height "H-pipe", which yields a much more consistent / predictable discharge. You can see it in the video below.
My goal was to setup an automated continuous water change system, but now I think that it would be better to setup a simpler system that does a daily 0.5 - 1.0 gallon water change over a period of about 30 minutes (at an optimal time of day). With that approach, it would be much easier to control salinity, since the timing of the water change could be coordinated with the timing of the auto-top off to ensure a consistent end state.
Note that the skimmer was running with its pump speed at the highest level before, during, and after the water change. Also note that I replaced the flow adjustment valve on the skimmer outlet (rotating vertical gate valve) with a custom non-valved, fixed height "H-pipe", which yields a much more consistent / predictable discharge. You can see it in the video below.
I am in the middle of a year long study of skimming a fish only aquarium and relating scientific studiies of protein skimming of BSA and other organics to skimming aquaria. My data confirms what has been said before on this topic
* wet skimming removes more organics per hour than dry skimming. The difference is large compared to dry skimming
And therefore, wet skimming is a more effective at removing organic impurities than simply siphoning out tank water.
A second conclusion is that if you can replace the tank water often enough to avoid large salinity changes, AND you are interested in removing more organics from your system, wet skim as much as you can. I routinely remove 1% of fifty gallons (~185 liters) per day.
When I get the data fit for viewing, I will post it here later this year, or at least an excuse for why it's delayed.
* wet skimming removes more organics per hour than dry skimming. The difference is large compared to dry skimming
And therefore, wet skimming is a more effective at removing organic impurities than simply siphoning out tank water.
A second conclusion is that if you can replace the tank water often enough to avoid large salinity changes, AND you are interested in removing more organics from your system, wet skim as much as you can. I routinely remove 1% of fifty gallons (~185 liters) per day.
When I get the data fit for viewing, I will post it here later this year, or at least an excuse for why it's delayed.
thank you! :thumbsup:
saveafish
New member
A little secret that no one tells. Organically broke down compounds has different molacure strustures in different stages. This attaches to the bubbles in different height/weight charges. Heavier molecules break the bubble structure at verging density during the rise.
Small example.. ever watch close, real close and see bubbles go down or sink. It's because there is a fat heavy protein ridding it. Bubbles don't sink in water. All bubbles above that waterline in the shimmer has something attached on it.
This is why taller skimmer are better. Greater the gravity pulling the bubble up causes it to carry a heavier load of molecules..
Small example.. ever watch close, real close and see bubbles go down or sink. It's because there is a fat heavy protein ridding it. Bubbles don't sink in water. All bubbles above that waterline in the shimmer has something attached on it.
This is why taller skimmer are better. Greater the gravity pulling the bubble up causes it to carry a heavier load of molecules..
Preliminary data from a protein skimmer study.
I began a skimmer study to ensure maximum waste removal and to clarify what is being removed. My DYI skimmer was made from 24 inches of 4 inch PVC pipe, operated with a water down flow of 60 gallons per hour countercurrent to an air flow of 6 liters per minute through a basswood aerator. Over several months, skimmate samples, taken just after the skimmer was cleaned, were analyzed for color, NH3, PO4, and two phytoplankton species. Results seem to confirm that wet skimming removes more material per hour (higher recovery rate, light colored skimmate) than dry skimming (higher enrichment, smaller amount of darker skimmate often accompanied by a solid deposit on skimmer surfaces).
Color Removal Rate
Molecules that color the skimmate yellow to brownish likely represent a range of organic species. Measuring color intensity with a Color of Water Hanna Checker provided a means of estimating the amount of color producing molecules in terms of PCU's (color intensity reported in platinum cobalt units). Full disclosure: the correlation between color intensity and the amount of color producing molecules in the skimmate is a reasonable but untested assumption of this approach.
To calculate the amount of color removed per hour, the foam collection rate in liters per hour is multiplied by the color molecule concentration in PCU's, giving the relative amount of material removed in units of PCU liter/hour. The graph of the data below indicates a substantially greater amount of colored material removed with increasing foam rate, i.e., wetter skimming removes more material per hour than dryer skimming.
Ammonia Removal Rate
I know, skimming does not remove inorganic molecules, but I looked for ammonia anyway. The salicylate method indicated a low level of ammonia but the amount varies in a seemingly random fashion and is not correlated with the rate of skimmate collection (see graph). Organic amines are known to interfere with this method and may explain the presence of ammonia in the test. I am doing more work to understand this situation.
Phosphate Removal Rate
I looked for phosphate in the skimmate knowing that it shouldn't be concentrated by foam fractionation. The data seems to indicate that it might (see graph) and the amount possibly correlated to foam rate. The mechanism for phosphate removal is not clear to me. Is it adsorbed to particles, inorganic or organic? Is it being liberated by the acidic conditions of the test? Further work is planned to understand this.
Phytoplankton Removal Rate
I selected two phytoplankton to observe in the skimmate that were easily identified by their features, one a dinoflagellate and the other a diatom. Both species cell count seemed to be correlated with foam rate (see graphs below).
Future Work
I will post results seeking to explain ammonia and phosphate in the skimmate. I am also attempting to develop a simple method for measuring the relative amount of dissolved organic compounds in foamate.
Sent from my iPad using Tapatalk
I began a skimmer study to ensure maximum waste removal and to clarify what is being removed. My DYI skimmer was made from 24 inches of 4 inch PVC pipe, operated with a water down flow of 60 gallons per hour countercurrent to an air flow of 6 liters per minute through a basswood aerator. Over several months, skimmate samples, taken just after the skimmer was cleaned, were analyzed for color, NH3, PO4, and two phytoplankton species. Results seem to confirm that wet skimming removes more material per hour (higher recovery rate, light colored skimmate) than dry skimming (higher enrichment, smaller amount of darker skimmate often accompanied by a solid deposit on skimmer surfaces).
Color Removal Rate
Molecules that color the skimmate yellow to brownish likely represent a range of organic species. Measuring color intensity with a Color of Water Hanna Checker provided a means of estimating the amount of color producing molecules in terms of PCU's (color intensity reported in platinum cobalt units). Full disclosure: the correlation between color intensity and the amount of color producing molecules in the skimmate is a reasonable but untested assumption of this approach.
To calculate the amount of color removed per hour, the foam collection rate in liters per hour is multiplied by the color molecule concentration in PCU's, giving the relative amount of material removed in units of PCU liter/hour. The graph of the data below indicates a substantially greater amount of colored material removed with increasing foam rate, i.e., wetter skimming removes more material per hour than dryer skimming.
Ammonia Removal Rate
I know, skimming does not remove inorganic molecules, but I looked for ammonia anyway. The salicylate method indicated a low level of ammonia but the amount varies in a seemingly random fashion and is not correlated with the rate of skimmate collection (see graph). Organic amines are known to interfere with this method and may explain the presence of ammonia in the test. I am doing more work to understand this situation.
Phosphate Removal Rate
I looked for phosphate in the skimmate knowing that it shouldn't be concentrated by foam fractionation. The data seems to indicate that it might (see graph) and the amount possibly correlated to foam rate. The mechanism for phosphate removal is not clear to me. Is it adsorbed to particles, inorganic or organic? Is it being liberated by the acidic conditions of the test? Further work is planned to understand this.
Phytoplankton Removal Rate
I selected two phytoplankton to observe in the skimmate that were easily identified by their features, one a dinoflagellate and the other a diatom. Both species cell count seemed to be correlated with foam rate (see graphs below).
Future Work
I will post results seeking to explain ammonia and phosphate in the skimmate. I am also attempting to develop a simple method for measuring the relative amount of dissolved organic compounds in foamate.
Sent from my iPad using Tapatalk
wiggleharris
New member
I do it that way all the time.
Similar threads
