Evaporation

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catmel

Aquarium Advice FINatic
Joined
Apr 20, 2008
Messages
660
Location
Findlay, Ohio
Need some insight on this.. So far so good with my 55 gal, though I'm noticing I'm getting a lot of evaporation. Right now I have a standard hood with one strip light ( I believe only about 40 watts) that came with the tank. I know its not the best, but hey.. it was free! the guy forgot to charge me for my hood when I got the tank. I'm saving up for a good lighting system - I plan on keeping it FOWLR for at least a year until I get more experience under my belt.

Anyway, Ive noticed that the salinity seems to be fluctuating a bit. I did my last PWC on wednesday and had the specific grav at 1.022, I checked today and it was 1.022-1023. Before I had noticed it creeping up to 1.024 just within a few days. I have my lights on generally 10am-9pm. Would a better strip light (eg: coral sun etc) be better to help this / better for the fowlr until I can get a good lighting system?? or do I just need to cut down on my time I have the lights on etc?

thanks for the help!
 
Just add a little bit of freshwater to the tank every day, or every other day to make up for what evaporated. Lighting itself causes very little, if any evaporation.
I add over 3 gal/day to my tank to make up for evaporation.
 
Ok I usually do end up adding about a half gal every day, just didnt know if this was normal ;) Seemed during cycling, I didnt have to add much, and when I started keeping the lights on, I started noticing it. - I guess just paying more attention, since I have a fish in there now!

Just have to keep a better eye on that I guess ;)
 
I've got a 46g and during the summer I'm topping off with a little less than a 1/2 gallon per day, so your setup seems about right.
 
I have noticed the temperature of my house seems to affect evaporation If my house stays cool about 70degrees my tank evaporates less than when my house is like 78degrees Maybe its just me? My tank evaporates about 1 kool-aid pitcher of RO/DI water daily. I have a sump and I can usually go 3days before I have to fill with RO/DI. The water is about 1.023 when sump is full and about 1.025 when the sump is running low after 3days. I also have a auto dispense drip container that I fill with RO/DI and it slowly drips water into the sump so I only have to worry about it like every 5days. It makes life easy and also prevents a drastic change in Specific Gravity.
 
yes yes I use ro/di for top offs :p
Auto top off? Thats nice! I think I'm just having a bit of trouble with it being 90 outside, we just have two window ac's we run most of the day, but luckily itkeeps it about 72 in here, the tank is about 78 according to the thermometer.

thanks for the info, just need to keep up with my top offs. Does it seem to evaporate less in the winter iwith you guys or about the same? ( usually my house is about 70 then )
 
Boy, I'm glad someone asked this question. I was thinking something was wrong as I'm adding about a gallon of water a day (that's about 2 kool-aid pitchers :p)
 
i have to top off my 40 twice a week now (about 1 1/2 gals), where in the winter it's maybe once in two weeks and i have to add a heater to keep the temp up. i fortunately don't have to worry about salinity since i only have freshwater. i dont have central air either. just a big window unit.
 
I top off twice as much per day during July/August than I do the rest of the year.

For me, most of it is because the hot months are when I run the clip on fan to keep the temps down. The clip on fan alone will cause a huge increase in the evaporation rate - which makes sense because that's how it cools things down. Evaporation takes energy, and that energy loss is what helps bring down the temp of the tank.

For other folks, it could be air conditioning. A/C will dry out the air, and drier air will allow for quicker evaporation.
 
First i must say you dont want to cover your tank. You need good air flow above the surface for proper gas exchange. This is your O2 source as Salt water fish get there oxygen from the water and from saturated oxygen not from air bubbles large enough to see. Then your best bio filters , the LR and LS will convert ammonia and nitrate into nitrogen then released at the surface but if your tank is covered then your O2 is low and bio filters cant work as it should.

Then evap. is normal , my 75 evaps around 6 gallons a week. I use a doser and 5 gallon jug to keep it topped off. But keeping it around the same level is best. As it evaps then salinity changes and in a smaller tank can change fast and the constant up and down isnt wanted. In fact the top off unit is a very easy DIY and help reduce time of maintaining and increase time for viewing.
 
First i must say you dont want to cover your tank. You need good air flow above the surface for proper gas exchange. This is your O2 source as Salt water fish get there oxygen from the water and from saturated oxygen not from air bubbles large enough to see. Then your best bio filters , the LR and LS will convert ammonia and nitrate into nitrogen then released at the surface but if your tank is covered then your O2 is low and bio filters cant work as it should.

Then evap. is normal , my 75 evaps around 6 gallons a week. I use a doser and 5 gallon jug to keep it topped off. But keeping it around the same level is best. As it evaps then salinity changes and in a smaller tank can change fast and the constant up and down isnt wanted. In fact the top off unit is a very easy DIY and help reduce time of maintaining and increase time for viewing.

Oh I know :) I try to keep the 'doors' on the top open when I am home, otherwise I keep them closed due to my very curious cats, I dont want expensive sushi for them lol. There is a good amount of open space in the back, where it is cut out for the filter and skimmer. I know its not the best, but I'm working on it :) As of right now, I only have one 1" clown in there right now. I'm looking into getting a better lighting system, when I do I'm going to put eggcrate or wire over the top then.

thanks for the help on the evaporation issue. :)
 
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If yo have only a fish or 2 then they might recieve enough O2 but as they grow and you add more stock then your water O2 saturation will be very important. And covering the top just wont do it.
If you want use an eggcrate type material to cover. This allows good gas exchange with some security.

You cant cover your salt water aquarium as this gas exchange is vital to its health.
 
Catmel, that 40watt light fixture you have is probably fine while you only have fowlr. The fish don't need a whole lot of light. Now if you want your tank to be brighter or you want to turn it into a reef, that is a different story. Then you would need to upgrade. Personally, I would save my money on the lighting upgrade for when you are ready to get coral.
 
...There is a good amount of open space in the back, where it is cut out for the filter and skimmer. ...

With all that open space in the back, I wouldn't consider this covered then. If you end up having a low pH issue though, you might reconsider.

Sounds like the same type of setup I have, except my two glass pieces are suspended on shelf sliders (the front portion slides under the back portion... it doesn't hinge) so there's some air gap between them also. I've never had pH or O2 issues.
 
thanks kurt + ryshark. Its a typical top, with glass under where the one strip light sits, plus two small 'doors' at the very front of the tank that cover the front. They're propped open a bit from the cord for the powerheads as well. Also like I said before, has a big space cut out in the back for the skimmer and filter. I've had no problems with PH or o2 saturation.. ph is 8.2 and has been since setting up, fish are non stressed and eating well - so thats not the question / im not concerned. Just getting everyones view on how much was normal for water evap per day on a summer day.

thanks for all that helped, question answered :)
 
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