Is evaporation a good thing?

[johnnstacy]

Other then the fact that it cools a tank, is there any other benefit to evaporation. I use a chiller now so the fans aren't as critical as they once were but I wondered if there is any other benefit to evaporation and replacement of lost water.

[sir_dudeguy]

Imo its good. doesnt hurt anything anyways, as long as you dont let it evap a ton.

but i would think that having the fans on there which cause a more rapid evap would give you a better gas exchange, which will help your pH stay high. So if you're having pH problems, try getting more gas exchange before you try doing other things. In any case, it cant hurt anything by adding the airflow.

[philagothos]

I don't know of anything good it accomplishes. You should be getting sufficient gas exchange from your skimmer, overflow, pumps and anything else that causes turbulence at the surface of the water. In theory, if you could eliminate evaporation and still get sufficient gas exchange you would be able to eliminate all of the time & money spent on topping off a system and also have a more stable system due to eliminating another cause of instability. If you're using a chiller then you can probably ditch the fans without any problem. My fans also serve the purpose of keeping my bulbs cool and giving them a longer life.

Just my thoughts,
-Kevin

[sir_dudeguy]

yes if you've got all that stuff (which by the looks of your sig you do) then the gas exchange shouldnt be a problem. Evap is a really good way of cooling tho, but you've got the chiller, so if you can maintain proper gas exchange like said above...no need for the fans other than for lights.

[Agu]

Evaporation is over rated imo...........

[philagothos]

Can you clarify Agu? Over rated how? Overly emphasized as being important? Overly emphasized as being a hassle with topoff? MORE INFO!!!!














Please. :)

[sir_dudeguy]

yeah how is it overrated? imo, its the easiest way to cool a tank, and for us with money being an issue, the only option as we cant afford fancy chillers.

[philagothos]

My other option is to use my whole house chiller. :) I like it cool, so I keep it around 70 in the house. As a side benefit my tanks stay cooler. :)

[Merredeth]

Actually, I prefer the fans as well. I use one that I figged up that manages to disperse the heat from the lights very well thus keeping my tank more stable.

As for top-offs, they aren't any big deal to me. I just drip that in too and everything is a-ok.

[GlobaLPimP]

<a href=showthread.php?s=&postid=7967922#post7967922 target=_blank>Originally posted</a> by philagothos
My other option is to use my whole house chiller. :) I like it cool, so I keep it around 70 in the house. As a side benefit my tanks stay cooler. :)

ME TOO:D

[sir_dudeguy]

merredeth. i'm in the same boat as you. I just run a 10" box fan right next to my tnak that blows into the lighting and over the water. Evap is higher than it was...only about a gallon every 2 days tho, but that may be because the humidity is like, 80% in my room lol. cant evap much more :) but it does keep the tank that extra 3 or 4 degrees cooler nonetheless, and my lights are never hot.

[Merredeth]

<a href=showthread.php?s=&postid=7969484#post7969484 target=_blank>Originally posted</a> by sir_dudeguy
merredeth. i'm in the same boat as you. I just run a 10" box fan right next to my tnak that blows into the lighting and over the water. Evap is higher than it was...only about a gallon every 2 days tho, but that may be because the humidity is like, 80% in my room lol. cant evap much more :) but it does keep the tank that extra 3 or 4 degrees cooler nonetheless, and my lights are never hot.

I seem to go through more than five gallons every other day between all the tanks but in all honesty, I don't care about that as much I care about those lights running so hot during the summer.

Because I like to drip the water into the tank due to the amount of evaporation I came up with an idea to make a water change look better to the eye and simultaneously keep stress to my tanks friends to a minimum.

Recently, I finished a plant stand that is made of some cheap wood and then I covered it with mirror so it looked nice next to one of my tanks. When I'm not dipping water into the tank, I just stick a plant on it and it looks nice, plus the wood isn't getting all wet and it makes for easier clean-up and reduces the wood damage should I have some kind of small spill that I miss.

I like the plant stand so much that I'm thinking of making a few others so I can put them next to the tanks permanently rather than dragging out ladders.

The only change I am going to make to the typical box column design is I'm going to recess the piece the wood sits on and make a separate top so I can literally drop the jug into the stand and take a separate top off, so the only thing you can see is the tubing which can easily be hid in the back of the stand and then the tubing will go behind the tank or drop into a fuge (depending on which tank).

I won't get to it until the winter but I'm thinking anybody with ceramic tile or marble on their floors could cover the wood with ceramic or tile to make it more of a piece of art that actually does something useful for your tanks.

[DgenR8]

For those of you that are aiming a fan directly at your lights, you should read up on some of Sanjay Joshi's stuff here
http://www.reefkeeping.com/issues/author/sj.php
You're having a negative impact on par and color by blowing cool air right at your bulbs.

[wds21921]

So the best alternative is to actually cool the water itself then and not the lights per say?

[DgenR8]

Your lights, be they MH, VHO, PC, or T-5 are designed to run at a certain temperature. By aiming an air stream directly at them, you alter the running temp, and change the color (and par, I believe) of the light emitted.
A fan blowing air directly across the surface of the water will go much further toward cooling your tank, and won't effect light color.

[johnnstacy]

I missed a big point in my original post regarding another benefit of evaporation. In my tank, I have a kalk stirrer in line with the top off water. All top off water passes through that kalk solution and into the tank. Well, if you have little to no evaporation, then I have much less saturated kalkwasser entering the tank also. Turn on the fans!

[sir_dudeguy]

good point dgen...I'll definatly try that and see id it really does have any affect (hopefully not cuz its really easy for me to put my fan right where it is lol :) )

[WaterKeeper]

<a href=showthread.php?s=&postid=7970529#post7970529 target=_blank>Originally posted</a> by johnnstacy
I missed a big point in my original post regarding another benefit of evaporation. In my tank, I have a kalk stirrer in line with the top off water. All top off water passes through that kalk solution and into the tank. Well, if you have little to no evaporation, then I have much less saturated kalkwasser entering the tank also. Turn on the fans!

Yes there are some that go to extremes to get evaporation going so they can dose KW. My own feeling is that evaporation is just a maintenance headache with the only advantage in that it provides some minor cooling. As to dosing KW there are other methods to supplement calcium and alkalinity without needing to evaporate a third of a tank of water each day. ;)

[wds21921]

I read through it completely and I didn't notice anything stated by Sanjay about cooling of the bulbs being a factor? Maybe I missed something?

I could see a huge amount of air possibly being a factor but not an average size 3"- 4" fan making that big of a difference in the spectrum. I would think that the light would simply pull a little more energy to insure it's burning where it's designed too?

[DgenR8]

I thought it was one of Sanjay's articles, perhaps it was one by JBNY that explained the downsides of cooling bulbs while they burn.
I'll look for the exact quote.

[wds21921]

I'm just wondering if it's theoretical or fact thats all?

[DgenR8]

I took it as fact, but still have yet to find where I saw it.

[sir_dudeguy]

what about a 10" box fan? would that be considered a huge amount of air over a 55?

[DgenR8]

I have a 20" box fan blowing on my sump, and an 8" inside my canopy to go with my 3 four inch fans.

[philagothos]

I'm curious about the ideal operating temperature of our bulbs. I use T5s and the amount of heat they generate seems to vary quite a bit with whether or not I have the reflectors on them or not. Without the reflectors they run noticably cooler. Also, the canopy temperature varies a lot based on how many bulbs I have running. It seems there are many things we do that drive up the operating temperature of our bulbs. Is there a chance we might drive it up too high in a fully enclosed canopy?

To make a blanket statement that any fan blowing cool air across a bulb seems like too much of a generalization to me. I've also read that too much heat is bad for our lights as well. Somewhere there is probably a happy medium that varies from one bulb type to the next, maybe even from one manufacturer to the next.

With my 4" computer fan blowing down the length of my bulbs my canopy temp stays about 80 and on top of the reflectors (easiest place to place a thermometer near the bulbs) it measures about 110.

Just my thoughts,
-Kevin

[wds21921]

Hmm fan on the sump...... sounds like an even better idea.

If you read it as fact I'm fine with that.

I'm with WaterKeepers mind set. Forcing evaporation makes no sense. By speeding up that process wouldn't you also be driving up some other levels that might normally remain stable? CO2, etc?

[WaterKeeper]

Larry,

I think the drawback in force cooling metal halides is from what is known as "sputtering". That is where metal from the heated filaments cools and condenses on the outer tube. You'll sometimes see this as a darkened film appearing on the tube. This results in loss of output and, in some cases, spectral shift.

[Agu]

<a href=showthread.php?s=&postid=7967824#post7967824 target=_blank>Originally posted</a> by Agu
Evaporation is over rated imo...........

Sorry for the slow reply but I was gone for a day. Before we left I had to make sure all tanks were topped off and the topoff drip was set slowly enough to keep parameters even while I was gone. If it weren't for evaporation I could go away for a few days and leave the tank unattended. But instead someone has to come over and topoff every day :rolleyes: .

I too use the "whole house chiller" and have no desire to increase evap for cooling purposes.

However I do drip kalk so there's an upside to evaporation. But if evap could be eliminated I'd happily swith to a two part ca/alk additive.

Pretty much agree with Waterkeeper,



My own feeling is that evaporation is just a maintenance headache with the only advantage in that it provides some minor cooling.

[Agu]

Regarding fans on MH bulbs,

LAMP COOLING:1. All Photo Optic metal halide lamp bases must be kept below 230ºC (446ºF) during operation to prevent premature lamp failure. If convection cooling is inadequate, forced air-cooling may be used. Please see OSRAM literature for cooling requirements of specific lamp types. 2. If forced air-cooling is used, care must be taken to direct airflow at the bases only. Striking elsewhere on the lamp with the airflow will result in poor lamp performance or premature failure.3. Discoloration, surface pitting, and/or corrosion of the lamp connections indicate a thermal overload. To obtain optimum lamp performance, components exhibiting these conditions must be cleaned or replaced.
--------------------------------------------------------------------------------

From,

http://72.14.209.104/search?q=cache:gbslil_LXdoJ:www.sylvania.com/content/display.scfx%3Fid%3D003673676+Cooling+metal+halide&hl=en&gl=us&ct=clnk&cd=8

[DgenR8]

Not exactly how I remember it, but I'll take it! Thanks, Agu.

[philagothos]

That article deals with MH & mercury lamps. Does anyone know if the same applies to the various flouresent bulbs we use? I'm sure that too high or too low is likely detrimental to them as well, but I would like to see an something that details the various safe temperature ranges.

Agu, thanks for the clarification on your earlier post about overrated evaporation. I agree totally.

[wds21921]

I was going to ask same question phil in regards to especially VHO since I assume it operates at a higher temp?

[Agu]

<a href=showthread.php?s=&postid=7978169#post7978169 target=_blank>Originally posted</a> by wds21921
I was going to ask same question phil in regards to especially VHO since I assume it operates at a higher temp?

I doubt VHO operates at a higher temp than MH. But since I'm the only one with access to Google search give me a day or two .

;)

[WaterKeeper]

Fluorescents don't operate anywhere near the MH range. For most the temp is 77°F but for the T-5's it is 95°F. That is because they are designed for closer spacing. This is optimal temperature and the temp where their lumen output is rated.