Evaporation!!

[hockeydude15]

I just got started in sw. I have a 40 gal tank with about 2in bed of sand and 45 lbs of lr on the way. 1 protein skimmer and penguin bio. The tanks been established for about a month now, and ive noticed that I have an extreme evaporation problem. I replace about 1 gallon every two days. This makes me feel that its going to be very hard to maintain the tanks system at a stable setting. I get crystals of salt on everything around the tank, im assuming this is because the h20 evaporates leaving the salt? I have a hood but it doesnt seem to do all that much. Anyone have any suggestions?

[Kurt_Nelson]

Sounds like you have a fair amount of surface agitation causing a lot of "micro splashing" if you're getting dried salt crystals everywhere. That could be part of the issue.

I've got a 46g, with a semi-glass top (split glass top on plastic sliders, so it's not really air tight) and I see anywhere between 1/2 quart to 1 quart evaporation a day, depending on the room conditions - just to give you a comparison. If you've got salt everywhere around the top of the tank, it sounds like it's pretty open on top (which you want) so I'd expect you'd get quite a bit more evaporation than I see... so your numbers don't seem excessive in my opinion.

Evaporation is something you have to keep on top of with frequent fresh water top offs. But a gallon a day doesn't cause that drastic of a salinity swing - for a 40 gallon tank at SG 1.0250, if you lose 1 gallon of water through evaporation and don't replace it, your SG is only raised to 1.0256. Granted... you want to keep it consistent, but in my opinion that little of an increase over 24 hours isn't that much.

[Devilishturtles]

I get about a half gallon a day of evaporation in my 45 gallon with a full open top, so about the same as you. Every 2 days I just top it off with some freshwater and all is fine.

I agree with Kurt that you must have a lot of surface agitation to cause the salt everywhere. Unfortanetly though, the evap is normal.

[ken_wied]

I have a 250 gal, and I replace about 5-7 gallons every 2 days. Is this a drastic swing in salinity? Im working on plumbing a RO/DI top off unit directly into the sump, but finding the time to do it is harder than i thought I just run a python into the sump to top off.
Thanks!

[ccCapt]

I lose about 1.5 gals/day from evaporation on my 75. I think alot has to do with the MH's and 3 fans in my canopy. I add about 3 qts in the AM and 3 in the PM.

IMO, it's better to add top off water every day or multiple times a day if possible. It's all about stability.

[melosu58]

Originally Posted by cccapt

IMO, it's better to add top off water every day or multiple times a day if possible. It's all about stability.

I totally agree.

[Kurt_Nelson]

Interesting... from the numbers folks are putting up here, looks like people are getting about 1% to 2% of their tank capacity per day evaporating away. Mine is less than 1%, but as I mentioned, I kind of have a glass top while most people go topless!

[fijiwigi]

that makes sense you know if you go topless you are bound to get a sunburn. LOL

[austinsdad]

I use a 37g FW reservoir with a JBJ auto top off unit. Mounted under the stand. My 155 runs thru that in about 1.5 to 2 weeks.

I have a 250 gal, and I replace about 5-7 gallons every 2 days. Is this a drastic swing in salinity?

I'd measure to find out if it were me.

[cmor1701d]

I have a 45 gallon brute as a resovoir with a JBJ ATO connectedt ph going to my overflow. It lasts about 3 weeks on my 125.

[ellisz]

I lose about 3 gal / day on my 350+ system. I use a DIY auto topoff that I have been using for over 4 years. Auto top off should be on every tank, IMO

[hockeydude15]

Hah, I cant imagine replacing 3 gallons a day