Wet Skimmate Water Changes?

[Randy Holmes-Farley]

Thanks.

I'm not sure which metals you are referring to, but many of them, like copper, are nearly completely bound by organics in normal seawater. Consequently, they would not be skimmed differently than "organics", but they are removed in skimmate.

Also, free dissolved metals not bound to organics won't be attracted to an air/water interface and won't be skimmed at all.

 

[crazzyreefer]

Most metals only bind in the last phase of bubble rise/formation, typical skimmers (under tank/hang on back) actually strip the bubble before its fully formed. The result is only the removal of oils and mostly organics. My friend that did the test was the lab tester for a large sewage treatment plant.

 

[Randy Holmes-Farley]

Most metals only bind in the last phase of bubble rise/formation, typical skimmers (under tank/hang on back) actually strip the bubble before its fully formed. The result is only the removal of oils and mostly organics. My friend that did the test was the lab tester for a large sewage treatment plant.

That's the part I do not believe, at least for seawater. Metals bound to organics will bind with other organics, and those not bound to organics will not be skimmed at all.

 

[crazzyreefer]

Randy, if you run the residue from the neck of a off the shelf production skimmer through a GCMS you will find a high concentration of non-organics, but if you do the same test with the skimmate you will find very little. Over and over the test we did came out with the same results, yet when I test the skimmate from my foam, all the organics and non-organics are present. The foam doesn't dissipate, and this has to do with travel time.

Now I never tested "wet skimmate" it might reveal that instead of binding to the neck it will be washed out with the skimmate, But my instinct tells me that the neck is coated with organics, much like a fully formed bubble and is attracting them/catching them. This is an important factor to define, because if this is true then wet skimming is not removing the non-organics, yet the flawed design of a skimmer is.

 

[Randy Holmes-Farley]

I'm not sure what you mean. What nonorganics are you detecting by GCMS?

I agree that there are lots of nonorganics in skimmate, things like calcium carbonate, but they are generally not detectable by GCMS, and are present in skimmate. Ken Feldman showed that in this article:

http://www.advancedaquarist.com/2010/2/aafeature

 

[pscott99]

I'm not sure what you mean. What nonorganics are you detecting by GCMS?

I agree that there are lots of nonorganics in skimmate, things like calcium carbonate, but they are generally not detectable by GCMS, and are present in skimmate. Ken Feldman showed that in this article:

http://www.advancedaquarist.com/2010/2/aafeature

Thanks Randy for another good read :bounce3:

Did I read right "Cl" as in chlorine ?? Deadly ??

 

[JohnnyB in SD]

I am using the wet skimmate method to perform daily 5gl water changes within a 45 minute period on a 120gl system.
Will this do anything do alleviate sulfate buildup from dosing Epsom Salts?
Is there a practical way for the layman to test for sulfur/sulfate content in saltwater?

 

[Randy Holmes-Farley]

Thanks Randy for another good read :bounce3:

Did I read right "Cl" as in chlorine ?? Deadly ??

It is listed as chlorine atom, but just for identification. If it were present in the chlorine (Cl2) form, it would be a big problem. But as the chloride (Cl-) form, it is the single most common thing in seawater other than water.

 

[pscott99]

It is listed as chlorine atom, but just for identification. If it were present in the chlorine (Cl2) form, it would be a big problem. But as the chloride (Cl-) form, it is the single most common thing in seawater other than water.

Ahhhhh much better. Thanks again.

 

[crazzyreefer]

Randy, the H&S skimmer is a ok production model, but the bubble rise is about 8", at this contact time, the removal is completely different. If a person took his Honda around a test track and told me a cars top speed is 125 mph, but we know that's not the truth, its 125mph for that Honda.The results published For most people will be more or less accurate, but this isn't the same thing as the skimmer I built. The non agitated contact time is the most important. Ill dig up my results in storage.

 

[swilliamson]

This thread may be about water changes via wet skimming and it seems some folks interpret that to mean periodic wet skimming for periodic water changes, but it needn't be restricted to periodic water changes. Just like the fellows in the beginning of the thread found, skimming a little wet continuously takes care of skimming and water changes for you automatically. I've been skimming ~0.75% of my system volume daily as my sole water change for a while now and both my tank and I are loving it! (That roughly equates to a 5% weekly or 20% monthly water change.)

Pros and cons as I see them:

Pros:

- Skimming a bit wet reduces my skimmer maintenance
- My water-change workload is reduced to refilling a reservoir of saltwater--the system deals with removing the old and replacing with new for me.
- Lower stress on the tank inhabitants (no drastic changes to water parameters)
- Easier maintenance means it is more likely to get done.
- Waste-water for changes has more gunk than taking it from the display/sump.
- Almost house-sitter proof​

I do believe wetter skimming removes more DOC than dry skimming. (To paraphrase Randy, less water draining from the foam = less organics draining with it.) Whether that's 0.0001% more or 50% more, and what the cost/benefit is regarding producing the make-up water are both unanswered questions. However, if I am going to be removing roughly the same amount of water anyway doing water changes, the cost is close enough to the same whether I remove it with a skimmer or some other means. That leaves the question of just how much more effective is wet skimming at removing DOC. That's another fine question for another thread, but to me it is enough to know that the answer is definitely "more".

Cons:

- Continuous water changes use a bit more water on an annualized basis for the same effect. See Randy's article in the October 2005 issue of Reefkeeping for more on that.
- If you don't have access to drain the skimmate and have to manually do so, reduced workload may not be as big of a factor for you.
- May be more capital intensive and has more parts to potentially fail than manual water changes and manual skimmer-cup cleaning.​

Feel free to check my math (not my strong suit), but for folks considering combining wet skimming with a continuous water change system, here are some rough equivalents:

10.00% monthly = 2.40% weekly = 0.35% daily
15.00% monthly = 3.68% weekly = 0.53% daily
20.00% monthly = 5.02% weekly = 0.73% daily
25.00% monthly = 6.42% weekly = 0.94% daily
30.00% monthly = 7.90% weekly = 1.17% daily​

 

[bimmer88]

What color skimmate is everybody getting??? Just did this for the first time and my skimmate is not quite coming out that tea color everybody is saying they are getting... attached is a picture of my skimmate next to a bottle of regular water... you'll see that it's just slightly cloudy but there is almost no color... that was from 4 hours of wet skimming... how long does it take you guys to get about 5 gallons of skimmate??

 

[reefling]

I am curious about the colors of skim ate as well. How are people making these big collection cups? I have a 5g bucket with a screw on lid. Also, it seems like vacuuming sand would be more productive.

 

[psykobowler]

I have been using this wet-skimming water changes technique and I can attest that it works and saves me a lot on buying salt. My skimmer cup drains through a hose to the side of my house so the cup never overflows. Every 3 days or so, I perform this technique modified to my liking. First I clean my skimmer neck, then I check my salinity. If the sg is 1.025 I add saltwater to my sump to raise it an inch. If the sg is 1.026 I add ro/di water to raise it an inch. My skimmer will skim really wet until the sump level goes back to normal. At this time I also add vodka to the tank. I believe that during this wet skimming period the skimmer skims out additional bacteria that helps reduce nitrates and phosphates on top of the organics. This technique plus vacuuming the sump for mulm and cleaning the refugium/chaeto weekly helps keep my water clean and saves me a ton on buying reef crystals salt. Before I was changing 100 gallons of water per week but I deemed it unnecessary. I am glad I ran into this thread.

 

[chercm]

thanks a lot for these pictures

when the skimmer sucks fluid instead of air, it stops making bubbles and stops working. I put it below the standpipe as this is a better scenario than skimmer cup overflowing into the sump.

Here are a couple of quick pictures.

Another overall shot showing the vent:

The skimmer cup with the intake for my two venturi pumps going in the lid on the left. The black tape is so I know how far in the cup to push the tubes. the center is the stand pipe that goes to the sump and to the right of it is the 1/4" drain to the collection container that then goes to house sewage. I have to put a pipe cleaner in the 1/4" drain every so often as it can clog up:

Here is a top view of my collection container with the standpipe drain to sump next to it:

Here is a look at the collection container. See how clean the 1/4" polyethelene line to house sewage is? It has never been cleaned in the years it has been in use:

Hope this helps.

 

[Stockpickinguru]

Interesting, hadn't thought of trying this. Definitely going to try it. Makes good sense.

 

[sabbath]

I'm looking at this idea. What are the best methods?

I'm thinking of over filling my sump and putting a bucket on my skimmer cup.
How fast do you add the water to the sump? It appears to me that we would want to add the water slowly, like with a aqua lifter pump. This way the skimmer has time to make new skimate.

 

[marcusbacus]

How can this be adapted to a RSM 250? My skimmer was (still is, sometimes) overflowing, as it's fairly new, and sometimes I just turn the skimmer off and "syphon out" the collection cup to remove the excess of water when I don't really want to perform a full cleaning. It's not a huge amount of water this way (tea coloured, always), but if I let the skimmer on, it can be used to collect more water as explained in the method.
But how can I replace the water, if I don't have an auto method to refill it with salt water? Does it need to be done as fast as it seems (sorry if I misunderstood it)? Can I just collect the amount of water I want (say, 5%) then just use regular water premixed as in a regular water change? I think so, as the main reason of this method is to get the "filtered" water out of the tank right off the skimmer as it removes the junk, instead of just using a syphon.

 

[Beachbw68]

Is one skimmer better another?

 

[Bladez]

I shoot for a 5 gallon bucket +/- per day on my system ~500 (actual) gallon system. Ideally you want to skim out as much junk as you can before adding any new water to the system other wise you dilute your results.

So, my goal is for 30 gallons at at time or about 6% water change per week.

I'm looking at this idea. What are the best methods?

I'm thinking of over filling my sump and putting a bucket on my skimmer cup.
How fast do you add the water to the sump? It appears to me that we would want to add the water slowly, like with a aqua lifter pump. This way the skimmer has time to make new skimate.