Skimmate Drops Salinity Way Too Much

[MHG]

So the only think I can think of that is causing my salinity to drop is the skimmate. However it is going from 1.025 to 1.023 in a week with only about 1 cup of skimmate. Foe a 75 gallon total volume does this make sense?

I have no leeks and zero creep...

[bdare]

So the only think I can think of that is causing my salinity to drop is the skimmate. However it is going from 1.025 to 1.023 in a week with only about 1 cup of skimmate. Foe a 75 gallon total volume does this make sense?

I have no leeks and zero creep...

Makes no sense.... Has to be something else.

[nanojg]

Thats not possible, how are you measuring?

[bertoni]

That's too much change for that amount of skimmate, I agree.

[bdare]

Isn't skimmate "salty" anyway???

[bertoni]

Yes, so when the skimmate is replaced by fresh water topoff, the salinity of the tank drops a bit.

[bdare]

*slaps forehead*

[Rybren]

:facepalm:

Thought I'd give you a hand.

[bdare]

:facepalm:

Thought I'd give you a hand.

Haha! Thanks

[matt frizz]

I don't think it could be the skimmate. It wouldn't be that drastic of a drop in that short period of a time.

[fishflorist]

1 cup skimate does not sound like be able to drop the salinity so much, in a 75g tank.

unless you are using a huge skimmer , like which they are using in a 750g tank.

[fishflorist]

suppose x gallon skimate is replaced by RO water ,

(75-x)/75=1.023/1.025

x=0.146gallon

if this math is right, then it now make sense to me. This is possible.

[fishflorist]

Sorry , I guess my math is wrong. Here is a better one I think ?

1.023 = 31.3ppt
1.025 = 33.9ppt

so the math should be :
(75-X)/75=31.3/33.9

X=5.75gallon

so actually if you skim out 5.75 gallon saltwater and replece with RO water will drop your 75g system from 1.025 to 1.023. someone please check the math ?

[Randy Holmes-Farley]

Yes, that's correct. :)

[MHG]

Sorry for the slow replies... For some reason reefcentral was not emailing me any replies to my question. I know it makes no sence. I have a refractometer and I calibrate it at every use. Granted when I first started using it, my reading were all over the place but I think my methos is producing much more stable reading the past month.

Well, I have no leakes and very low creep. It is obviously going some where. I think I may splurge for a better hydrometer...

Since you all are better at the math than I am, bow much salt does it take to make up the difference in 75 gallons of water from 1.023 to 1.025. If the enswers match what I needed to add slowly over the past week, then my methods for measuring would be sound...

[porksmash]

During the calibration do you need to adjust the refractometer? If the ambient temp is stable and you are gentle with it it shouldn't wander and I wonder if refractometer adjustments are causing these weird readings.

[bdare]

Sorry for the slow replies... For some reason reefcentral was not emailing me any replies to my question. I know it makes no sence. I have a refractometer and I calibrate it at every use. Granted when I first started using it, my reading were all over the place but I think my methos is producing much more stable reading the past month.

Well, I have no leakes and very low creep. It is obviously going some where. I think I may splurge for a better hydrometer...

Since you all are better at the math than I am, bow much salt does it take to make up the difference in 75 gallons of water from 1.023 to 1.025. If the enswers match what I needed to add slowly over the past week, then my methods for measuring would be sound...
ditch the hydrometer all together and get yourself a Sybon Refractometer from Premium Aquatics.

[bertoni]

23/25 = .92, so you'd have to lose about 1 - 0.92 = about 8% of the water and replace it with freshwater, but that's assuming unbounded precision on the measurement.

[Randy Holmes-Farley]

Since you all are better at the math than I am, bow much salt does it take to make up the difference in 75 gallons of water from 1.023 to 1.025. If the enswers match what I needed to add slowly over the past week, then my methods for measuring would be sound...

I don't think that necessarily follows. If either or both readings are incorrect, just because the change in reading is appropriate doesn't mean the absolute readings are.

[MHG]

Well today is the 7th day siunce I discovered my dropping salinity... Each Day I calibrate my refractometer, test and double check by using the calibration fluid a second time. Todays reading 1.024. I also use a swing arm hydrometer. That one shows my current salinity at 1.023.


I have added a table spoon into my overflow each day tp bring it from 1.023 to what it is today. That .4375 cups . At the recomended rate that is about 1 gallon of salt water so I guess that is not allot of salt? That is why I asked the math question... I am not sure how much I need to add to bring it back up to 1.025. I would like yo get it back to that point safly so I can then pay closer attention to see where the drop is accuring or try different things like turning off the skimmer for a week to see how that effects it.


Although I am running biopellets so I probably need to empty the reactor before I shut down the skimmer.

[Randy Holmes-Farley]

No, that is not much at all. One cannot really do much math with salt mixes since the amount of moisture in them is variable, but a half cup might make up a gallon of seawater, and adding that to 60 gallons only brings the salinity up a little, say from 1.0240 to 1.0244. :)

The best way to raise salinity is to replace evaporated water with salt water, not by adding dry mix. To go from sg = 1.023 to 1.025, you'd add about 5 gallons of seawater to 60 gallons of tank water over however long that took. :)

[Habib]

MHG,

What kind of liquid and in which amount do you add to your tank?

For example stuff like vinegar, vodka, kalkwasser etc.....


Do you have to add freshwater to the tank because of evaporation? Is the water level in the tank / sump rising?

[MHG]

I run my ATO through a kalk reactor. The return secion is usually fluctuates within an inch this time of year... I am also dosing calc and alk but as I have very low amounts of coral right now it only takes 2ml a day to keep my calc at 450'ish and my alk at 9.8'ish.

Biopellets...No vodka, except in the OJ...

[MHG]

Well I can probably fill up a couple of galon poland spring water jugs with some higher salinity seawater and pour in a glug or two each day...

[Randy Holmes-Farley]

Yes, that is a fine way to go. :)

[MHG]

Thanks Randy...