J & Jr Posted April 5, 2007 Share Posted April 5, 2007 In my new tank with all th pumps and lights the temp swings from 78.5 at lights on to 83.2 at lights off is this a acceptable range? is 83 to high the old tank never went above 80.5, just need to know if I need to invest in some new fans(laugh) Quote Link to comment Share on other sites More sharing options...
impur Posted April 5, 2007 Share Posted April 5, 2007 I'd say you are right at the high end. 83 doesn't scare me, but 84 starts to. Walmart has some plastic housing fans with 2 speeds for just under 6 bucks. The work great for my sump evap cooling. Quote Link to comment Share on other sites More sharing options...
J & Jr Posted April 6, 2007 Author Share Posted April 6, 2007 just learning about this new tank I was was suprised at the rate of evaperation I lose about 1 1/2 to 2 gallons a day and thats without a fan. which I will be picking up tomarrow Quote Link to comment Share on other sites More sharing options...
CCR Posted April 6, 2007 Share Posted April 6, 2007 Your ok for now. But the heat is comming!!!! How about a fan in the hood. Not on the back blowing air in, but one on the top to pull the hot air out. Quote Link to comment Share on other sites More sharing options...
bluecheese Posted April 6, 2007 Share Posted April 6, 2007 Given your set-up I am wondering if your lights are too close to the surface. Do they generate a lot of heat? Once you add a fan or 2 you'll cool down and that should decrease evapporation. Quote Link to comment Share on other sites More sharing options...
illcssd Posted April 6, 2007 Share Posted April 6, 2007 It actually won't decrease evaporation ime. It increases it having the air blowing over the water like that. Quote Link to comment Share on other sites More sharing options...
impur Posted April 6, 2007 Share Posted April 6, 2007 It actually won't decrease evaporation ime. It increases it having the air blowing over the water like that. (agree) (agree) Yep, thats the basic concept. The air movement moves heat away from the tank and increases evaporation thereby cooling the tank. Quote Link to comment Share on other sites More sharing options...
J & Jr Posted April 6, 2007 Author Share Posted April 6, 2007 we will see how today goes I have a 6" fan blowing across the sump. "Given your set-up I am wondering if your lights are too close to the surface. Do they generate a lot of heat? Once you add a fan or 2 you'll cool down and that should decrease evapporation." Thats why I went with T5's I thought they had less heat problems, the lights are about 3 1/2" from the water is this to close? With the amount of evap. I feel I need to get on the auto top off very soon. Quote Link to comment Share on other sites More sharing options...
Nyles Posted April 6, 2007 Share Posted April 6, 2007 How big of a tank is this? Quote Link to comment Share on other sites More sharing options...
J & Jr Posted April 6, 2007 Author Share Posted April 6, 2007 It's a 75gal with about a 30 gal sump. now that I know how to post pic's I will start a build thread in members tanks this weekend if I can find the time between easter egg hunts:) Quote Link to comment Share on other sites More sharing options...
reefgeek84 Posted April 6, 2007 Share Posted April 6, 2007 3" is close to the water, I am sure they are also helping trap the heat. People claimed that T-5's did not heat up the water, but when I had them, they heated up my water... Quote Link to comment Share on other sites More sharing options...
Nyles Posted April 6, 2007 Share Posted April 6, 2007 thats a lot of evap, I would cool down those bulbs some more, my tank is double the size and you are evaping more than me. Quote Link to comment Share on other sites More sharing options...
J & Jr Posted April 6, 2007 Author Share Posted April 6, 2007 I just may have solved part of the problem, have been watching temp closely and caught one of the heaters still on at 80.1 and I had turned it way down yesterday hoping to start the day at a slightly lower temp. seems it stuck on(scary) I pulled it out and plan to replace it tonight. That may solve part of the heating and evap. problems we'll see Quote Link to comment Share on other sites More sharing options...
bluecheese Posted April 6, 2007 Share Posted April 6, 2007 Who can do the Maths? DOH! It actually won't decrease evaporation ime. It increases it having the air blowing over the water like that. Are you picking on me?(clap) Well yes I agree with that, but now comes the mad mathematical and philosophical equation. So as you increase wind and decrease temperature which direction does your evaporation go? Since evaporation E is directly proportional to Temperature T (E=a*T) and the speed of the wind S increases E by a factor x but also decreases T (from t1 to t2) by a factor y we have (E from fan= x*S -(t1-t2)*y*S , thus E = a*T + (x-[t1-t2]*y)*S. If the lamp source generate heat Then as height increases , T (from lamp heat effect) decreases of a factor h*T. The new equation is then E= (a-h)*T + (x-[t1-t2]*y)*S. Therefore find the ideal height h equal to your evaporation coefficient a (this will remove the temperature variable associated with evaporation (rock2) , then determine the ideal temperature swing (t1-t2) needed to equal your wind evaporation factor divided by the temperature change evaporating factor( x/y) (this will eliminate the Wind evaporation factor). Et Voila! E=0 (laugh). So the real important question is where is the cheese?(nutty) Still with me? (wife) I agree with Nyles you have a lot of evap. Would adding a canopy help with the evap? (it might also increase heat and we are back to the mad equation). Quote Link to comment Share on other sites More sharing options...
Lowman Posted April 6, 2007 Share Posted April 6, 2007 Well yes I agree with that, but now comes the mad mathematical and philosophical equation. So as you increase wind and decrease temperature which direction does your evaporation go? Since evaporation E is directly proportional to Temperature T (E=a*T) and the speed of the wind S increases E by a factor x but also decreases T (from t1 to t2) by a factor y we have (E from fan= x*S -(t1-t2)*y*S , thus E = a*T + (x-[t1-t2]*y)*S. If the lamp source generate heat Then as height increases , T (from lamp heat effect) decreases of a factor h*T. The new equation is then E= (a-h)*T + (x-[t1-t2]*y)*S. Therefore find the ideal height h equal to your evaporation coefficient a (this will remove the temperature variable associated with evaporation (rock2) , then determine the ideal temperature swing (t1-t2) needed to equal your wind evaporation factor divided by the temperature change evaporating factor( x/y) (this will eliminate the Wind evaporation factor). Et Voila! E=0 (laugh). So the real important question is where is the cheese?(nutty) My head hurts now Quote Link to comment Share on other sites More sharing options...
wegotjs Posted April 6, 2007 Share Posted April 6, 2007 Please stop crazy talk . GoIng tO Exploood YES OR NO ANSWERS FROM NOW ON Quote Link to comment Share on other sites More sharing options...
180Bob Posted April 7, 2007 Share Posted April 7, 2007 Actually W = ((Pw-Pa)(0.089 + 0.0782*V)/Y)*3600 Where W = Rate of evaporation at the surface of the water level (kg/h m2) Pw = Vapor pressure at saturation taken at the temperature of surface of water, in kPa Pa = Vapor pressure at the dew point according to the temperature of the ambient air of the room, in kPa V = Air velocity above at the surface of water, in m/s Y = Latent heat necessary according to the change of state of the water vapor at the temperature of surface of water, in kJ/kg And since the vapour pressure of water is approximately an exponential function of temperature the water loss is an exponential function of temperature. Also since the rate of evaporation is approximately proportional to the air velocity above the surface of the water. It should be much more effective to blow outside air directly at the water surface. If you don't use outside (by outside I mean outside of the hood or enclosed sump) then the partial pressure of the water in the air stream will approach the equilibrium vapor pressure at the tank temperature. In this case Pw will approach the value of Pa and W will approach zero. Quote Link to comment Share on other sites More sharing options...
CCR Posted April 7, 2007 Share Posted April 7, 2007 X = 1 and 1= M then Y= 3 another words X = M +1 combine and make 3=Y Quote Link to comment Share on other sites More sharing options...
180Brandy Posted April 7, 2007 Share Posted April 7, 2007 X = 1 and 1= M then Y= 3 another words X = M +1 combine and make 3=Y This is true in the universe where 1 = 0. Quote Link to comment Share on other sites More sharing options...
bluecheese Posted April 7, 2007 Share Posted April 7, 2007 Well done 180 Bob! So John. I think its clear: Start relocating to the space station! You can even swim with your fish then! (nutty). OK seriously. Sounds like a canopy might help limiting evaporation some? But that's not the answer you are looking for. (scratch) Quote Link to comment Share on other sites More sharing options...
dsoz Posted April 7, 2007 Share Posted April 7, 2007 I just may have solved part of the problem, have been watching temp closely and caught one of the heaters still on at 80.1 and I had turned it way down yesterday hoping to start the day at a slightly lower temp. seems it stuck on(scary) I pulled it out and plan to replace it tonight. That may solve part of the heating and evap. problems we'll see Forget about all of that math nonsense. Look for the mechanical problem. I hope that solved it for you today. Dsoz Quote Link to comment Share on other sites More sharing options...
CCR Posted April 7, 2007 Share Posted April 7, 2007 This is true in the universe where 1 = 0. Simple Biology Quote Link to comment Share on other sites More sharing options...
bluecheese Posted April 7, 2007 Share Posted April 7, 2007 Simple Biology Right on CCR ! Why keep it simple when you can make it complicated? John> I almost asked you if you had checked your thermostat. But I assumed that would be the first thing you would do. DOH! Hope the problem is solved. It's a good thing to know that we have some very talented people who can do the maths around here. (clap) Quote Link to comment Share on other sites More sharing options...
reefhut Posted April 7, 2007 Share Posted April 7, 2007 I might add a couple of thing's to help your cooling... - You could run a fan in your hood area(Blowing outside air in the hood) just below the bulbs, to deflect heat from the water. - You could run your lights on a shorter time period to reduce water heat up. - Most important...Make sure your heater is set to come on at bout 74 degrees. Also don't scimp on a heater purchase. Buy a nice unit for a few bucks more, get something titanium with an external controller. - If your running an internal sump return pump, be sure the thing is not running hot. Reach in the sump area and put your hand on it. If so, replace it or clean it out. Cheers' Quote Link to comment Share on other sites More sharing options...
J & Jr Posted April 9, 2007 Author Share Posted April 9, 2007 Thanks for all the sugestions I guess it was stupid of me not to check the heater sooner but it had worked fine for quite a while and when I checked in the morning the temp was low78.8 and just seemed to climb durring the day so I asumed it had to be because of the lights. the only thing I had changed. I had been hanging the lights from the ceiling with string and the lights had been about 5"to 6" above the water and with the new brackets they are only about 2 1/2" to 3" since the new heater water has stabilized and evap has slowed consideribly. Thanks John Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.