Wet Skimming --> Salinity Decrease = ?

landlord

New member
Hello folks, thanks in advance for looking.

Here is my situation. I tend to skim on the wet side of the fence for no better reason than, pulling out a nice volume of green tea colored skimmate each day, sometimes twice a day.

This in turn forces the A.T.O. to replace this lost salt water volume woth RO/DI.

The water volume is 90 gallon + water in sump / skimmer / fuge/ CA Reactor..... lets say another 25 gallons tops = 115 gallons in the system.

I water change religiously 15 gallons per week.

I notice that I have been seeing a decrease in salinity (as expected) from the wet skimming to the tune of as much as .002 - .003 in SG (.003 this week only since I cleaned the skimmer and it began really skimming wet. It has been dialed back a bit to compensate). During the water change this forces me to load the new water up with a higher SG to get the tank back to 1.026 at the end of the change out.

I am not observing anything outright bad with my SPS. They are all adding to their skeletons and doing their thing. Those with good color are retaining their color (Tricolor, Birdsnest, various Monti's, etc). Those on the browner side of the color fence are remaining on the brown side, which bugs me, I want colors like everyone else lurking this forum.

Is this gradual salinity swing over the course of each week doing damage that I am not aware of, aside from what I mentioned above? Should I be concerned with this wet skimming regimen? I cannot be the only one who deals with this change in salinity in smaller volumed tanks.

Thoughts, Questions, Comments, General Harassing.

Thanks again for reading,

--landlord
 

asonitez

Floodicus Maximus Flooris
i have been wondering this same thing. I have a similiar setup and I tend to skim on the wet side of things. I get about a 1/2 cup or so a day. I'm interested to know if my wet skimming is throwing my SG off a lot.
 

Kip

New member
i dont use SG.... but i've seen corals unhappy with a swing from 35 to 31ppt before. (faded, then went dark when i upped it) I think a tighter swing from 35-33 (which should translate into a near equal swing that you are seeing) shouldnt be a problem if it is happening over a week's time.

From what i understand in the wild... during big rain storms, the salinity can really fluctuate in localized areas.
 

landlord

New member
I guess the week it takes to drop in salinity is OK but now I am starting to think that the restoration of salinity during the water change, might be happening to quickly, or is this just paranoia.

1 week to go from 35 ppt to 33 ppt
15 minute water change to restore it to 35 ppt (Is this troubling???)

--landlord
 

Kip

New member
could be... i've no experience with it... i wet skim, but the percentage i remove in relation to my TSV doesnt make mine swing that much. that and my wet skim isnt nearly as wet as yours.

i havent measured it.. but off the top of my head.... i skim about 1-2 gallons per week on 450gTSV ... so for me, it is negligable
 

LobsterOfJustice

Recovering Detritophobe
You can always add some saltwater in with your topoff water... say you skim out 2 gallons over a week, and refill your topoff every 2 weeks, when you fill the topoff up, add 4g of saltwaterin the reservoir.
 

Canarygirl

New member
I've had this happen to me while skimming wet, and it did negatively affect my acros.

I agree with adding some SW to your RODI topoff water while you are skimming wet. Monitor your sg daily while getting things dialed in.
 

landlord

New member
Canarygirl - What problems did you observe? What was the swing in salinity? and over what period of time?

I am not really keen on adding salt to the RO/DI storage tank.

If any measures are taken because of possible issues it would probably be to skim less wet. Again I am really happy with the way the tank is going with my current maintenance routine in place, but am simply curious of any "Unforeseen as of yet negative effects".

Thank for your replies --landlord
 

Canarygirl

New member
well for me it was a 2 to 2.5 point drop in salinity over the course of about 3 weeks. Salinity got down to 1.022 and Alk dropped from 7 dhk to 5.8 at the same time. Then I had some STN in a few corals.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Skimmate generally has a salinity similar to the tank water, so if you remove substantial amounts, just replace an equal volume with salt water. It is a good way to perform small water changes. :)
 

uncleant

New member
i just got a new skimmer and when i was reading the directions it said that when wet skimming your salinity will drop because its still technically pulling out water i guess idk
 

LobsterOfJustice

Recovering Detritophobe
Randy and Roland, thats pretty much what I was getting at, but by putting it in the ATO reservoir you dont have to worry about manually adding it.
 

landlord

New member
Many thanks :)

Being that there were minimal responses (thanks canarygirl :) ) to possible side effects of the salinity drop I will simply just do what has been said. I set up a small vessel of saltwater so as too add a quart of it per day to match the skimmate going out to keep the salinity better balanced during the week.

LoJ --> Since I haven't yet plumbed the skimmer to a drain I have to manually muck with the skimmer each day. Just one more step to reintroduce saltwater vs salting the 65 gallon RO/DI storage vessel (big PITA since I never let it fully drain and it is pretty much sealed).

Thanks all, much appreciated --landlord
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Randy and Roland, thats pretty much what I was getting at, but by putting it in the ATO reservoir you dont have to worry about manually adding it.


:thumbsup:

Sure, that works great, unless you dose something else in the top off. :)
 

landlord

New member
I (secretly) am kind of a closet survivalist, so on the off chance <or not-so off chance> that the Metro Cincinnati area goes under seige, I want to make sure that I have 65 gallons of pure h2o, just in case, so no additives in the top off for me.

:) You never know when you may have to barbeque that yellow tang for food.

--landlord
 
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