Wet Skimmate Water Changes?

[lokii_37]

I think this is an awesome idea. Your SW topoff tank could a very short tank. If it were 6"x24"x48" that would hold about 30g. It could lay flat on the floor of a fish room. Put a bladder connected to the skimmer cup in the tank and your good to go.

I think emptying 30g of skimmate would be pretty nasty thou.

 

[gaberosenfield]

30 gallons of month old skimmate at that!

 

[pledosophy]

Floor drain! Never empty the skimmer again

 

[spamreefnew]

I have been doing one gallon per week water changes via wet skimming on my 90 gallon system. I feel that this one gallon change of truly dirty water is the same as changing five gallons of "normal" water thus saving me a lot of money I would normally spend on salt.

 

[mindi]

yep great idea IMHO, and wetter the skim the more efficient it is also. I then just dose the replacement saltwater into my RO top up reservoir. I would love a floor drain but on a concrete floor and not against an outside wall I have no choice but to collect it.

 

[ttabbal]

I'd like to give this a go. I have a floor drain available, just need to connect up some tubing to drain the skimmer to it.

Am I correct that if I do this, then set the skimmer to run wet, and put 1.026 saltwater in the ATO, I'm going the right direction? I would also need to set up RODI for evaporation makeup, or set the ATO water to a lower salinity to compensate. Of course I will monitor salinity daily via refractometer and compensate for any swings.

 

[Elliott]

I'd like to give this a go. I have a floor drain available, just need to connect up some tubing to drain the skimmer to it.

Am I correct that if I do this, then set the skimmer to run wet, and put 1.026 saltwater in the ATO, I'm going the right direction? I would also need to set up RODI for evaporation makeup, or set the ATO water to a lower salinity to compensate. Of course I will monitor salinity daily via refractometer and compensate for any swings.

yes, as your skimmer removes skimmate, which has similar salinity to tank water, your ATO should replace that seawater loss with the same salinity seawater

your evaporative loss needs to be replaced with fresh water RO/DI, which can be estimated and periodically adjusted based on actual salinity measurements

 

[swilliamson]

I'd like to give this a go. I have a floor drain available, just need to connect up some tubing to drain the skimmer to it.

Am I correct that if I do this, then set the skimmer to run wet, and put 1.026 saltwater in the ATO, I'm going the right direction? I would also need to set up RODI for evaporation makeup, or set the ATO water to a lower salinity to compensate. Of course I will monitor salinity daily via refractometer and compensate for any swings.

You will still experience evaporation which ordinarily would be replaced with fresh water since evaporation leaves the salt behind. Your ratio of water loss to evaporation versus water loss to skimming will dictate your make-up water target salinity. The art in a wet skimming setup is in finding just the right salinity in the make-up water to replace the salt you're skimming out, while not causing the tank salinity to climb over time. This will take careful monitoring and it will likely change seasonally.

Depending on how wet you decide to skim and how much evaporation you have, if either of these is really small compared to the other, and your inhabitants can tolerate the swing, you can get away with just monitoring it and adjusting it periodically. In time, if you just run a fresh water top off from a container and find you need to add about a cup of salt each week to the tank to make up what you're skimming out, you can just add that cup of salt to the week's container of fresh top off water and the result is a more stable system. Continue to monitor and adjust from there. If you top off direct from a plumbed RO/DI, it is a bit more challenging to automate. My first idea would be to slowly dose a saturated saltwater solution in small quantities with a peristaltic pump similar to dosing two-part. Some aquarium controllers may be able to dose it as salinity drops below a trigger point if you trust that sort of thing.

 

[LouisianaReefer]

Using periodic wet skim water changes, some folks remarked at the aggrivation of resetting the skimmer back at the prior level for dry skimming. I have-first had experience that this can be a bit aggrivating at times. Once I set my skimmer to what I thought was appropriate and woke up the next morning with my skimmate reservoir full and water overflowing. I learned the hard way that it is never a good idea to set the skimmer without having time to observe it for a few hours.

Has anyone ever tried putting markings on gate valves to help reset the skimmer to prior, dry-skimming levels in order to reduce the guess-work? I am thinking of trying this. I doubt that it will be very precise, yet it should help.

 

[sonnus]

Using periodic wet skim water changes, some folks remarked at the aggrivation of resetting the skimmer back at the prior level for dry skimming. I have-first had experience that this can be a bit aggrivating at times. Once I set my skimmer to what I thought was appropriate and woke up the next morning with my skimmate reservoir full and water overflowing. I learned the hard way that it is never a good idea to set the skimmer without having time to observe it for a few hours.

Has anyone ever tried putting markings on gate valves to help reset the skimmer to prior, dry-skimming levels in order to reduce the guess-work? I am thinking of trying this. I doubt that it will be very precise, yet it should help.

Not sure if anyone has brought this up yet but a controllable DC needle wheel pump would be perfect for this as long as your base setting isn't already on the highest setting. When you want to wet skim you just bump up the pump speed and when you're done you drop it back down to your base setting.

Also, you could use your Apex to help maintain the salinity. Since the Apex is not terrific with the salinity accuracy you should be careful with this but it could keep it in the range better than manually checking it once a week. Basically, you would need 2 topoff containers, one for fresh saltwater and one for freshwater. You could just add the line in the code to your existing ATO code that if salinity is less than __ dose SW and if it is higher than __ dose FW.

 

[mindi]

Agree getting skimmer reset after an over organic event is a PITA. It applies to wet skimming as well as dry....slightly off topic but you refer to marking a gate valve . I would love that but for my main drain control valve..I have tried every type I can find on the Australian market and cannot find one worth marking because the operating range on them is so narrow that my overflow chamber can be altered from empty to full by tapping on a wing of the ball valve. Surely a finely controlled wheel operated ball or gate valve can be had somewhere in PVC. I have tried blade valves from USA...looked good..still no controllability.
I have actually found a way to do this really well and that is by building a branch off the main drain with a small cheap ball valve in it say 1/2" ...and get the flow right with the main branch and then fine tune with the trim valve. It works really well if you can be bothered with the 30 mins plumbing.
So to get back on topic our standard ball valves/gate valves tend to operate in too small an area to be worth marking...they are really intended for full on full off use.

 

[karimwassef]

Has anyone run two stage output gates to allow the option to run wet on demand?

The idea is to run dry most of the time, but trigger a second gate to partially close to initiate a wet "event" and flush for a few minutes before replenishing.

 

[jccaclimber]

Agree getting skimmer reset after an over organic event is a PITA. It applies to wet skimming as well as dry....slightly off topic but you refer to marking a gate valve . I would love that but for my main drain control valve..I have tried every type I can find on the Australian market and cannot find one worth marking because the operating range on them is so narrow that my overflow chamber can be altered from empty to full by tapping on a wing of the ball valve. Surely a finely controlled wheel operated ball or gate valve can be had somewhere in PVC. I have tried blade valves from USA...looked good..still no controllability.
I have actually found a way to do this really well and that is by building a branch off the main drain with a small cheap ball valve in it say 1/2" ...and get the flow right with the main branch and then fine tune with the trim valve. It works really well if you can be bothered with the 30 mins plumbing.
So to get back on topic our standard ball valves/gate valves tend to operate in too small an area to be worth marking...they are really intended for full on full off use.

I don't think there's a ball valve out there that will get you what you want. By their nature the flow resistance vs. valve angle on ball valves is steep and hard to control. Gate valves have a much longer control (rotation) per output (flow resistance). The downside to small changes is that they take a while to adjust. How much are you adjusting?
Using a gate and moving say 1/64 of a turn at a time, then waiting 10 minutes I would be surprised if you can't get the controllability you want.

 

[CFC_Surge]

Interesting read.

 

[Gary Majchrzak]

IMO it's the only way to roll :fish2:

 

[JonezNReef]

Wow I just discovered this thread. I have been doing this for a few years now. I will have my skimmer overflowing the whole time I am siphoning the tank out and by the time I have taken out about 20 or so gallons of water my skimmer has filled up a 5 gallon bucket or 2 to add to the water change. Glad Im not the only one that does a water change with the skimmer LOL:lolspin:

I plan to wet skim soon so that I am doing almost continuous water changes through out the week. I will still do a water change a few times a month so I can siphon the bottom of the tank out. What I plan to do is have two 5 gallon buckets, one inside the other. I have the bottom bucket drilled in the bottom with a bulkhead and a pipe that goes out and up to about half the height of the bucket and then drains into my return section of the sump. I have the bucket filled about to the same height as the exit pipe with fresh saltwater. I then have a second 5 gallon bucket floating inside that bucket that my skimmers collection cup drains into. As the skimmate fills up the top 5 gallon bucket it forces the bottom 5 gallon bucket of fresh saltwater to drain into the sump keeping the water parameters and salinity in check.

Even if this works I will still have my skimmer overflowing during water changes to assist with the siphoning.

 

[philipk2003]

Weekly 5 gallon water change

Weekly 5 gallon water change

Here is a picture of how I do my 5 gallon wet skim change.

I elevate a 5 gallon bucket of salt water and drip it into my fuge with an air line.

I adjust my skimmer to remove water at about the same rate.

Takes two hours.

LOL... I can make 20 gallons of salt water, siphon out 20 gallons of old water, and refill in 1 hour.

However, this way, I do not turn any equipment off and my fishies don't get scared!

 

[75mixedreef]

I've done that. It is time consuming but very efficient. The downside is that you cannot target certain areas to remove detritus or algae. Those factors together make it easier to just to a traditional water change after stirring everything up with a baster to the rocks. Once in a while I will do it for a gallon or two just to remove nutrients, not so much for adding back minerals.

 

[gernby]

Bumping this old thread to see if anyone has improved this water change method using the new controllable DC skimmers. I just setup 2 Reef Octopus Elite 200-INT skimmers in my 2 systems, and believe they will be perfect for continuous automated water changes without any adjustments.

I found that when the skimmer is at its max setting, it begins wet-skimming whenever the water level in the sump is above ~7". Once the level in the sump drops to the magic level (seemingly determined by bio load), the skimmate becomes dry. If I slowly add water to the system, the skimmate becomes wet again, and the discharge rate increases to match the rate being added. I believe that I could use a dosing pump to provide a continuous feed of new water, and let the skimmer extract excess water at the same rate.

Obviously, safe-guards would be critical, especially for salinity and equipment failure (overflows). However, assuming an "ideal" implementation with no failure points, how certain can I be that continuous wet-skimming wouldn't actually degrade water quality in some way? Do skimmers ONLY remove unwanted "stuff", or might wet-skimming result in a lower concentration of beneficial "stuff"?

 

[jccaclimber]

How will you correct for evaporation? The system will drift towards the input water's salinity, but not without some lag. You would need to top off an estimated amount, slightly lower your replacement water salinity, or rely on salinity measurements to make corrections.